I like the song for Sheila's Wheels, the car insurance ad featuring three blondes in a pink Cadillac, with a brass band sitting on the boot. It's just a fun song:
For ladies who insure their cars
Sheila's Wheels are superstars...
Anyone remember that joke poster that got set up around London a few years back for "Sheila, the new Australian perfume (also kills flies)"? Cosmetics departments all over London were inundated with requests from people who took it seriously, to the point that an Australian company that did actually market a perfume called Sheila decided to export it to the UK!