Website where you can select a song and it will generate a probabilistically "infinite" version of the song where it jumps back and forth between similar sections of the song. It's pretty impressive how well it works. It effectively simulates the feeling of having a song stuck in your head looping over and over. I'm a big fan.

To play a custom song, select "Pick a song" at the top. For some reason that button doesn't seem to show up on phone so go here to pick a song. Probably my favorite I've found so far is "No Sunlight" by Death Cab For Cutie, since that song is repetitive enough to link together in funny ways, but distinct enough in different parts that it doesn't just sound the same.

[Update: as of 2024/04/09, this site seems to have gone down. People periodically reupload mirrors of the tool though (with varying degrees of 'actually working'), so if I find another mirror of it that works I might update this.]