ha! the first thing i thought of when I heard the theme was "Fancy Colours" -- and lo, it's the TOTHK.
Chicago - Fancy Colours
Bad Company - Silver, Blue & Gold
Donovan - Mellow Yellow
The Beatles - Yellow Submarine
Electric Light Orchestra - Mr. Blue Sky
Foreigner - Blue Morning, Blue Day
Jimi Hendrix - Purple Haze
Peter Gabriel - Red Rain
The Rolling Stones - She's a Rainbow
Sting - Fields of Gold