red hot chili peppers
An incredible, kick ass band.  Known for fusing metal and rap to create a unique funk-like sound.  The band is is also capable of producing great melodies, and even balad-style songs.  They have been around since the mid 80s when they played a concert wearing nothing but a sock on a particular appendage, and have been rocking ever since.  The bass player, Flea, is perhaps the best bass player of all time, and the guitar player, John Frusciante, is also a titan of his instrument.

Great RHCP songs include:

Californication
Under the Bridge
Other Side
Aeroplane
Parallel Universe
This Velvet Glove
Higher Ground (cover)
and many more.

Undoubtedly one of the best and most visionary bands of all time.
The Red Hot Chili Peppers rock everyones' collective socks.