A series of battle-focused console games in the Pokémon series. They are all compatible with the corresponding handheld games in the series, though they can be played in a limited capacity without those games. Current games in the series are:
Pokémon Stadium (Japan): The first game in the series, which was only compatible with 42 out of the then-151 Pokémon; it was really just intended as a visual tool for tournaments, since those 42 were generally high-end competitive 'Mons, and wasn't intended to be a major consumer product. The sequel was out in Japan only a few months after Red and Blue were released in the US, and after their release in Europe, so this game was skipped in those regions in favor of the more complete sequel. Fans tend to refer to this as "Pocket Monsters Stadium" when needing to distinguish it from the commonly known US release.
Pokémon Stadium: Called Pokémon Stadium 2 in Japan, it was fully compatible with the Game Boy games, including support for all the Pokémon, and was produced as a much more complete product after consumers clamored for something more in the wake of the very simplistic first release. It included several tournament levels, a Gym Leader Castle to battle the Gym Leaders from Red, Blue, Green and Yellow, the Kids Club to play minigames, a Pokémon Lab to manage the Pokémon and items on your games, including trading and transferring Pokémon between games and keeping them on the N64 cartridge, and the Game Boy Tower to play the Game Boy games on the TV through the Transfer Pak.
Pokémon Stadium 2: Called Pokémon Stadium Gold/Silver in Japan, it was compatible with all of the first generation games as well as the second-generation games, Gold, Silver, and Crystal. It included most of the same features as the original Stadium, plus others such as an in-game Mystery Gift and a Trainers' School area where one could learn basic and advanced game concepts and even fight puzzle-style training battles.
This generation got the Pokémon Colosseum games instead of new Stadium games. While they did include some elements of the Stadium games, and included the ability to wage battles between Game Boy Advance versions of Pokémon on the TV, they had their own stories and included less of the utility and tournament functions of the Stadium games. (The utilities were put into Pokémon Box.)
Pokémon Battle Revolution: A Wii game, compatible with Diamond, Pearl, Platinum, HeartGold, and SoulSilver versions. Developed by Genius Sonority, the same team behind the Colosseum games. Not technically a Stadium game, but it counts here because of its return to the battle focus of those games- more so in fact, as it lacked the minigames and any sort of storage (which would end up in My Pokémon Ranch). Featured several different battle styles, Character Customization, and the ability to battle random opponents over the internet.
Notably, Generation V completely lacked any kind of Stadium title - the online battling was now handled by the DS games themselves. This has continued into Generation VI, with no Stadium-esque title announced for the Wii U, and with the storage utility, Pokemon Bank, being a separate app for the 3DS.
A juggler in Koga's Gym in the first Stadium has his name highlighted in pink because his Slowbro knows Metronome, which is impossible without cheating.
In Stadium, Mewtwo has infinite PP when you fight him. Granted, you're fighting him six against one, so it's hardly fair to throw stones...
Com Mons: You're pretty much guaranteed to run into at least two or three trainers with a Wigglytuff, a Butterfree, or both per tournament in Battle Revolution.
Double Knockout: Averted; Destiny Bond (if the user faints, so does the foe) fails in 1 on 1, while a trainer that uses a suicide move on their last Pokémon loses (even if they KO the foe's last Pokémon with it).
Drama Queen: Most Pokémon take a few seconds to go through their fainting animation, rather than just collapse. Especially noticeable when compared to animations in X and Y.
If you import your starting Pikachu from Yellow to the Stadium games, it has Ikue Otani's voice acting like in the Anime (and the Super Smash Bros. series), rather than using the standard cry.
In the first two Stadium games, a Pokémon with a certain pattern in its nickname (reversed syllables, one syllable followed or preceded by another word, etc.) changed the creature's color. It's pretty fun trying to figure out what patterns will cause what changes.
Completing the Master Cup in the original with a Pikachu in your party will give the player an opportunity to make Pikachu learn Surf. When Pikachu uses Surf in the game, it will use a surfboard in the move animation. In Pokémon Yellow, the overworld Surfing sprite will change to Pikachu on a surfboard. It will also allow the player to play an Excite Bike clone called "Pikachu's Beach" in a house south of Fuschia City. As a Call Back to this, in Battle Revolution, Surfing Pikachu can be unlocked as a Mystery Gift by completing the game.
Emulator: The GB Tower in the first two games is essentially a Super Game Boy that uses the Transfer Pak to read your game save. Naturally it only works with Pokémon games, but it does allow you to quickly access ingame features, training and such. Completing certain goals will even unlock the ability to speed up the emulation.
Silver in Stadium 2 ups the ante, on paper, by throwing in Lugia and Ho-oh with Mewtwo. Unfortunately, the former two have shared weaknesses, the latter was (mercifully) nerfed, and it's still 6 against 3. There's plenty of room for Self-Imposed Challenges, though.
Flawless Victory: Completing a match without losing a Pokémon gives you a continue. Building them up the early matches is quite helpful.
Flying Seafood Special: Some water Pokémon summoned into battle fall into this, especially the fish-like ones, who float aboveground as if they were in an aquarium (except, of course, for Magikarp...).
Luck-Based Mission: The "Challenge" Cup, which randomly generates your team (NOT your opponent's).
Mythology Gag: The Gym Leaders' castle sections reflect a certain Ascended Extra pair from the anime. Brock in the first Stadium game (Round 1) has a Vulpix and has a Forretress in the second game. Misty in the second Stadium game (Round 1) has a Togetic.
Forretress is an odd case of foreshadowing, as Brock's Pineco hadn't evolved yet in the anime at the time Pokemon Stadium 2 was released.
No Fair Cheating: The game highlights moves a Pokémon shouldn't learn in pink. This becomes most obvious in Generation 1, when trading from Generation 2, where Pokemon can learn moves they can't in earlier games, so it'll use the pink highlights even if the Pokemon is, in fact, completely legit. Fortunately, this doesn't actually affect your ability to battle.
Battle Revolution prevents the uploading of anything it reads as hacked-it turns the hack into a bad egg. Potentially annoying if it's legit but has a special event move that makes the game think it's hacked.
Obvious Rule Patch: The games introduced the standard clauses that typically get used in any "competitive" environment (in game or in versus battles). These include the Sleep clause (only one Pokémon a team can be asleep outside of self-inflicted sleep, such as with the Rest move), the Freeze clause (same as Sleep clause but with frozen solid), the Uber clause (Mewtwo, Mew, Ho-oh, Lugia and Celebi are banned) and the Double KO clause (see double KO). Without these, battles could get very boring. Pokémon Battle Revolution removed the legendary ban, though they were banned in online play for a while due to a glitch.
Old Save Bonus: The games are all very difficult without one of the handheld games, as the rental Pokémon usually have very poor movesets. Using a handheld game makes each game much easier.
There's also a few Secret Characters in Pokémon Stadium 2's minigames that are unlocked if the player has a certain Pokémon in thier party or box.
If the player has a Crobat, the player will be able to play as Crobat in Gusty Golbat
If the player has a Scizor, the player will be able to play as Scizor in ClearCut Challenge
If the player has a Girafarig, the player will be able to play as Girafarig in Furret's Frolic
If the player has an Omanyte, the player will be able to play as Omanyte in Tumbling Togepi
If the player has an Igglybuff, the player will be able to play as Igglybuff in Streaming Stampede
If the player is using Pokémon Yellow, the player will be able to play as Pikachu in Pichu's Power Plant
Save Game Limits: While the Nintendo 64 games only have one save file that accommodates all your games, Battle Revolution has four save slots, each one synced to one DS game. Which means that if you own all five games in Generation IV, one will miss out on playing PBR.
Mewtwo's animation when it uses Psychic and various other attacks looks suspiciously similar to the Kamehameha motion. Whoever animated his motion had taken a definite stance on the "Giegue or Frieza?" argument that Mewtwo's appearance has so often sparked.
Hitmonlee's faceplant when KO'd looks an awful lot like the Flair Flop.
Pay close enough attention to every game in the series and you'll notice that they only ever create new models for the new Pokémon. Even in the latest games, Gen I Pokémon still have the same animations as they did in Stadium 1.
Despite using the same models, Battle Revolution offered texture and special effects updates to the older Pokémon.
Surfer Dude: If a Pikachu knows Surf (which is obtainable in each of the games), a special animation will play if it uses the move, which consists of it riding a wave on a surfboard.
Trash Talk: Almost all of the Stadium 2 opponents will taunt you in some way, shape, or form. (The biggest exception being Red.)
The Unreveal: If Diglett or Dugtrio somehow manages to use the move "fly", they'll be animated as if their bodies are somehow made up of only their heads and the gravel around them (as this video demonstrates).
Up to Eleven: One of the announcer's lines in Battle Revolution uses this exact phrase.
Versus Character Splash: Before each battle in both Stadium games, Colosseum, XD, and Battle Revolution, you'll see who you get to face and their Pokémon. You and your Pokémon are also shown. Averted in the main story modes of Colosseum and XD.
Warmup Boss: In Stadium 2's Johto Gym Leader Castle, Jasmine of the Olivine Gym serves as the warmup boss since she will switch out her Pokémon to get the advantage on you plus her team is more varied unlike previous trainers and Gym Leaders. If you plan/react wrongly to Jasmine's switching, she will have the advantage and can defeat you. Though if you anticipate and react to her switching correctly, she can be pretty easy especially if you exploit her team's weaknesses. Jasmine basically reminds you that your future opponents can switch their Pokémon on you to give themselves the advantage over you.
Westminster Chimes: Used at the beginning of the "Clefairy Says" minigame in the first game, and for battles in Earl's Academy in the second.
The announcer has unique chatter for the following
Broken Record: One-shot an opponent's Pokémon at the beginning of a match, and you might get these three lines in succession: