I know that the days of the week are all named after Norse or Roman gods or the sun and moon, but I can't figure out what Tuesday is named for. Do you know?

Good question! You are correct, in English (and other languages) the days of the week all correspond to celestial objects or mythological gods.
  • Sunday: Sun day
  • Monday: Moon day
  • Tuesday: Tyr's day
  • Wednesday: Odin's (or Woden's) day
  • Thursday: Thor's day
  • Friday: Frigg's day
  • Saturday: Saturn's day

Tuesday is named for Tyr, the Norse god of combat and victory, as well as the god of law and justice according to other traditions. Tyr was far older than the other gods of Asgard, and some interpretations of his name translate it to mean "the sky god." Therefore, Tyr is probably the closest Norse representation to the Greek Zeus or the Roman Jupiter.