Nerf Herder

Nerf Herder is a pop punk band from Santa Barbara formed in 1994 by Parry Gripp (vocals, guitar), Charlie Dennis (bass) and Steve Sherlock (drums). They describe themselves as a "geek rock" band, and are known for simplistic modern punk-style songs with frequently humorous, juvenile and pop-culture-referencing lyrics. They are most noted for composing the theme tune to the television series Buffy the Vampire Slayer, and for their 1997 single "Van Halen", a tribute to the band of the same name, which attracted significant radio airplay and led to their first major record deal with Arista Records.

source: Wikipedia