Rubick spellsteals walrus punch, pretty normal. Rubick uses walrus punch by firing a projectile that's essentially himself to uppercut the enemy? Hillarious.
When Tusk uses Walrus Punch normally, the text "WALRUS PUNCH" appears in red letters above the unfortunate target. What happens when Rubick uses it? "STOLEN PUNCH" (or, if you hit Tusk himself, "SUCKER PUNCH").
An E-sports example. In the wild card game (the winner of which would go on to play in TI 3) between Rattlesnake and Quantic, there was a moment where Sven (played by Quantic's Sockshka) ambushed Chaos Knight, Gyrocopter and Beastmaster and attempted to stun them all with storm hammer so that his teammates could catch up to them and possibly kill them with few losses. In a very unfortunate case of a misclick, Sochshka cast storm hammer not on Chaos Knight, not on Gyrocopter, not even on Beastmaster, but on... Beastmaster's Boar, stunning absolutely nobody but the boar. This ended up getting Quantic team wiped with the exception of one. This moment can be seen in its full glory in this video.
Another example sort of from TI3: On the first day of the competition, an "all-star match" was held between two teams voted on by the players. Given that there was nothing at stake, the players took it upon themselves to goof off in the most spectacular way they could. Highlights include the members of Alliance (Loda and Akke) and Na'Vi (Dendi and Puppey) trash-talking their teammates, who were on the opposite team for this match, a completely ridiculous draft using heroes that are almost never used in professional games, such as Sniper, Omniknight, Skeleton King and Axe (the Dire side actually had an all-melee team), and Dendi celebrating killing Puppey (his captain) by getting out of the booth and dancing in front of Puppey. You can watch it here, starting at 11.02.30.
One of the changes to Bloodseeker's Thirst ability in the 6.79 patch was causing it to remove the speed cap when active. This had predictable results.
Fountain Hooking techniquenote For the uninitiated, the technique involves combining Chen's Test of Faith ability that sends an allied hero back to their home base with a perfectly timed use of Pudge's Meat Hook ability to pull an enemy unit toward Pudge. The result: a helpless enemy hero flying over otherwise-impassable terrain back to the fountain-hooker's base, where the base's automatic defense structure kills him very quickly. is awesome, flashy and all. And sometime it backfires...note Fighting fully stacked Chaos Knight without disabler nearby is a really bad idea.
Wraith King's new lines, some of them are outright references to CASPLOCK LEORIC.