In my halls last year I kept 3 snakes (Royal Python, Mexican Black Kingsnake and a baby Boa Constrictor) and a Crested Gecko.
Each were kept in appropriately sized black plastic tubs with internal lighting - at first I kept them hidden from view but half way through the year when it was clear there wasn't going to be any inspections or anything I started becoming a bit more relaxed with it, but it depends on the uni.
Depending on the species of snake then can be kept in Really Useful Boxes and easily hidden so snakes and geckos are a good choice!