The musician was good. The costume contest ensured continuous visual amusement. My fave costume for the evening: a homemade costume with a vintage zippered sweater (horizontal stripes on the top half) and a suspended diamond over the young man's head. I was puzzled, and R. didn't have a theory, so I walked over to the table The Sim was sharing with a Monk and asked. D'oh! Brilliant costume -- if I had played The Sims at any time after the 1990s (or if I had been younger and the game had left the kind of impression that games used to leave when I was young, like Space Invaders or Pong), I'm sure I would have gotten it faster.
There was only one pair of potentially offensive costumes. The rest were pretty good: a firecracker, a can of beer (it was Heady Topper, according to R.), plus the usual -- a Medusa, Thor, some Indiana Jones, a Boba Fett. Oh -- FroZone was awesome. Looked homemade, too.