Abosolutly anything Zelda. I started humming it in school once and my friend said, "What song is that!" and I was like, "umm....nothing..."

The Legend of Zelda Majora's Mask theme... Gosh all this Zelda talk is making me want to go on the N64 and start a new Zelda save slot ;o
Nope, too late I'm getting the game out xD who cares if it's 11:32PM :D

For me any Nintendo music, anything Mario or Zelda gets stuck in my head and I keep listening to it nonstop ,Why Koji Kondo??? why did you have to make such addictive music!!!