Coffee Quake 2, a collection of 132 player-created Quake maps, each with an expected play time of about five minutes- roughly the length of a coffee break.

https://www.slipseer.com/index.php?resources/coffee-quake-2-double-shot.213/

The maps' brevity keeps things feeling fresh. There's some unevenness but I can say this much for even the weakest inclusions: They're short.

The first Coffee Quake is also good fun.