I don't mean humming the main theme from your Zeldas, your Halos, your Metal Gear Solids. I mean some random piece of background music, shop music, menu music, etc., that isn't a featured part of the game's score, but nonetheless sticks with you.
For me as of late, with no warning, I've been getting the song from Tee K.O. from Jackbox Party Pack 3 stuck in my head. It's a pretty rad jam!
So what gets stuck in your head?