Emo Jump

Listen here, genius. The joke implies that emos are always sad, depressed, and possibly suicidal. So, when asked who can jump the highest, the punchline suggests emos are still falling because they jumped off a building or bridge. Basically, the joke is saying emos are so emo they jumped and haven't landed yet because they're, you know, dead. It's a dark joke, which is probably too sophisticated for your taste.