If you can find them, spiny mice are wonderful! Not jumpy like gerbils, not nippy like hamsters - no smell, not noctural, really love to be handled. You must have two - can be two males, two females or a pair (you'll have babies but the male helps care for them). I had two brothers at the shop, it was great because kids would hold them while their mom shopped. Only flaw: They pair off/mate for LIFE - if one dies, the other dies too. And that's exactly what happened - Ping got a lump (cancer) and died; Pong absolutely refused to eat, curled up under his water bottle and literally died of a broken heart. It was tragic. There was a margin of time when I could have introduced another mouse and hoped he'd take to him/her - but couldn't get one in time.
But still - a very unique and "safe" classroom pet(s). Google "Spiny Mouse" or "Chinese Spiny Mice" and see what you get!
Laura