Every time I’ve had to move into a new place, I catch myself humming at least one of the 3 Tetris songs without realizing it while packing boxes or a vehicle. Usually it’s Music-1 or Music-2.
Back when I was playing a bunch of Oblivion, I was doing the quest to find Nirnroot (Seeking Your Roots). I was spending so much time looking for them I started seeing them in real life out of the corner of my eye everywhere (it was usually actually thistle). I’d have to stop and look because I knew it was important, before my brain would kick in and I’d realize that it was from Oblivion.