What theme songs can you think of that were borrowed from previous hits?

George Lopez: "Low Rider" (War)
Bosom Buddies: "My Life" (Billy Joel)
Happy Days: "Rock Around the Clock" (Bill Hailey & the Comets)
Married, With Children: "Love & Marriage" (Frank Sinatra)

Drew Carey Show - Five O'Clock Morning by The Vogues
Cleveland Rocks by Ian Hunter (covered by The Presidents...)
Golden Girls - Thank You For Being a Friend by Andrew Gold (covered by ???)
Sydney (1990 Valerie Bertinelli) - Finish What Ya Started by Van Halen
Unhappily Ever After - Hit The Road Jack by Ray Charles
Family Matters (Season 1) - What A Wonderful World by Louis Armstrong

I'm not sure if this thread is limited to sitcoms, but here are some other than sitcoms

CSI - Who Are You by The Who
CSI: Miami - Won't Get Fooled Again by The Who
CSI: New York - Baba O'Riley

Hell’s Kitchen - Fire (Ohio Players)
F is for Family - Come and Get Your Love (Redbone)