The cutscene before the Tribal Stage begins with your creature banging a stick on the ground with glee while dramatic music plays. At the song's climax, it throws the stick in the air and...there's a record scratch as the stick bonks it on the head. Doubles as a CMoA for it reenacting the intro scene of 2001: A Space Odyssey.
It's especially funny if your creature doesn't have hands, or has them in unusual places.
The Bards in the Space Stage are essentially a space empire of Cloudcuckoolanders. Everything is a party to them, and it seems they have a fixation on cake.
In the intro scene for the Civilization Stage, your tribe is having what looks like a meeting to discuss their Civ's strategy. The chief asks for suggestions from the crowd, and he gets three answers. The first two are the Civ's "personality" (Military, Religious or Economic) and vehicles. The third answer? Pie. Cue everyone getting confused and the chief facepalming.
Clark and Stanley. That is all.
Some of the Epic Creatures can be hilarious looking.
One of the hardest challenges in the Space Stage is finding Earth, which bags you the "Manifest Destiny" achievement. But if you want to stay true to the Alien Invasion scenario and destroy Earth with a Planet Buster, you get the "Oh, The Humanity!" achievement.
Pretty much the fact that you can find and destroy Earth is pretty funny in itself.
When you domesticate an animal in the Tribal Stage, the villager who was given the order befriends the selected animal by...feeding it a dog biscuit, which makes said animal hop up and down a few times and change to your tribe's colors. The villager then gets out what looks like a shepherd's crook and drives it to a pen behind the village's hut while western music plays.
At the end of the Maxis adventure called "The Spirits Are Restless," after you purify the corrupted altar with the Wolf Staff, the Eldritch Abomination that haunted the forest disappears in a puff of black smoke as angelic lights shine down. The music sting "Ever After" plays over for a few seconds...and then the altar explodes and brings the music to a sudden end.
In nearly every Maxis-made adventure, there are hidden Easter Eggs where you'll find a lone Spoffit, small sheep that are the de-facto mascot of Spore Galactic Adventures. Generally, the area around the Spoffit will play Bluegrass music, so it can be pretty unfitting to find something so upbeat in an adventure like "The Spirits Are Restless."
The Creepy and Cute expansion pack added several new animations for the Creature Creator/Editor's Test Drive mode. Those that could fall under this category include Ballet (creature dances in place for a few seconds, then strikes a Level 3 Pose and falls over), Lightning (Exactly What It Says on the Tin), Bees (creature runs away screaming from a swarm of angry bees), and Blast (creature gets knocked on his backside). Bonus points if you had added the three babies.
Some of the descriptions of the relics found in the Space Stage can be like this. For example, the description for The Foot of Povey: "The awe-inspiring Foot of Povey. Povey himself claimed to be the rightful owner, but quite frankly, he didn't have a leg to stand on." And then for Amethysts, "This mysterious substance is 100% pure Amethyst."
Diplomat Empires in the Space Stage are easily comparable to the Vogons. One snippet of text after saving their colony from an Eco-Disaster mentions that they were deliberating on a Vote to Take Immediate Action...while you were handling the problem by yourself. At least the Ecologists have a tangible excuse, that being that they can't bring themselves to kill the infected animals because of the sad look in their eyes.
When you open communications with an Ecologist Empire you know, one of the greetings is the ambassador thinking you're an enemy invader and immediately surrenders...and then he sees you and declares a false alarm.
The first unlockable Bard tool gives your captain an improved Sing ability...that makes him sing in a female soprano voice. YMMV.
The Knot The Grawx empire, especially if it's friggin' huge.
If you pester a Grox colony long enough, they completely lose it and scream at you in anger.
Try bidding absurdly low for a star system in the space stage. Some of the reactions are hilarious
Trader: We were expecting a decent profit, not a visit to the poor house.
Ecologist: We thought you were our ally, not a bottom feeder.
Zealot: Do you think, since we are creatures of faith, that we are subject to delusion?
Bidding absurdly high can also get funny reactions on occasion
Intentionally-bad adventures are rife with funny moments; music in inappropriate places and overuse of the first page of tracks (especially Space Warriors being used in a fetch quest or Angelic Dream being used in a boss fight) , level design that looks like a kid made it, poor spelling for dialogue or thoughts, bad timing for events, and other such things can all make what would normally qualify as a bad adventure into a hilarious adventure.