make up your own song.
if you're committed enough to getting a song out of your head... just focus on making something up... i've found that if you put enough energy into something completely unrelated to the stuck-in-your-head song (thinking about math-rock is especially effective when combating 80s synth-pop or arena rock), it goes away.
speaking of stuck-in-your-head stuff... anyone familiar with the Louis Black "If it wasn't for my horse, I wouldn't have spent that year in college" bit?
How do you get an irritating song out of your head?
21if i got lasik surgery on one eye, i could wear a monacle.