The song game. I feel like a lot of people have come up with it naturally.

One person plays a song. The next person has to then play a song with some sort of connection to it. Like, you could follow the velvet underground's "Sunday Morning" with Nirvana's "Lithium" because it has the line "Sunday morning is every day for all I care". Any connection is valid so long as the group accepts it, but I prefer lyrical ones myself.

That's it. You go around until you lose interest.

I like it as a way to share music, because to do well you typically have to actually listen with their song.