The stars of the Midnight Marathon for me were definitely this couple on a tandem with a speaker trailer, blasting house music the whole way through (much of it by Ben Böhmer). Great fun to ride in their sonic shadow and I stayed near them for most of the whole return leg.
When I left the start line I was chasing a group with a sound system¹ in search of riding tunes, but I ended up passing them, and a few others. Eventually I caught up to the trailer and the surrounding pack, which had immaculate vibes and was going about ~12 mph which was a just-right pace for me.
¹ they might have been SCUL members, actually? they were all riding Contraptions. I don't see anything in the SCUL mission logs but I believe that not all rides get logged. I asked someone in the know. (Edit: yes, there was an unofficial cohort)