Somebody to love -- The Cable Guy. That Kareoke scene where Jim sings the song is the only scene in the hole movie I'll watch too, sadly.
Jimmy's version of I am the Walrus
Friendly World -- Man on the Moon
the WHOLE Soundtrack to Bruce Almighty! there's not a song on there I don't like.
Grinch 200 (duet with Busta Rhymes) -- The Grinch soundtrack
Ace in the House - Ace Ventura: Pet Dective. I wish that was on the soundtrack
The Riddler by Method Man, Kiss from a Rose by Seal & Hold Me, Thrill Me, Kiss Me, Kill Me by U2 - Batman Forever soundtrack
& the song Jim Carrey sang in "Yes Man" it's not in the soundtrack