I'll give you some more.
Carlos Vives
Les Luthiers (I don't know if they count as a music group. They make funny stuff with original instruments instruments. The lyrics of their stuff is hilarious, if you know spanish that is.)
Cruks en Karnak
Piero
Soda Stereo
Ricardo Arjona
And the BEST MUSICIAN OF ALL TIME, ILL MITCH.
Actually he is horrible but hilarious. He is a Russian kid that now lives in America but doesn't have very good English. He raps about skate-boarding, Boxing, Punching stuff, and other stupid stuff. Check him out.
http://www.illmitch.com