Nirvana/Funny

"C'mon, people now, smile on your brother, everybody get together, try to love one another RIIIIGHT NAEOOOW!"
At a show in Newcastle:

Kurt: Hi, my name is Kurt Cobain. I'm homosexual, I'm a pagan, I'm a drug abuser, and I like to fuck pot-bellied pigs!

The video for "In Bloom".
While the infamous VMA concert is in-between awkward and funny (they start playing "Rape Me" before going to "Lithium", Krist throws his bass up and gets hit by it in the head), Dave yelling "HI AXL!" is hilarious.
- For that matter, Axl's conflict with Kurt and Courtney was pretty funny as well. Seeing him walking by, Courtney asked Axl if he'd be the godfather to their child. Axl Rose was not pleased, and he strode up to Kurt, telling him to "shut his bitch up." Kurt turned to Courtney, jokingly saying, "Shut up, bitch!" Axl was not amused.
  - Nirvana did not like Guns N' Roses (especially Axl) very much.
The song "Sliver" as a whole.
The crowd at their first show requests "Heartbreaker". Kurt's response?:

Kurt: I don't know how to play it!

From the MTV Unplugged show, when guests The Meat Puppets are a little slow tuning up:

Kurt: What are they tuning? A harp? I thought we were a big, rich rock band, we should have a whole bunch of extra guitars".