I have one mouse and she is fine, but I think that she is very lonely. I used to have two mice (long story!). My friend's mouse and my one are going to meet in the holidays, so that's OK, I guess. Males tend to stink way worse than females, so heed my advice and get a girl. Yes, they are extremely friendly, just wash your hands before touching them, because they might smell food on you and bite down-hard. They are playful-kind of like dogs. Tickle them and stroke them and gently scratch them behind the ears and on their backs. They groom themselves constantly (they look like cats when they do this!) so you don't have to wash them. Don't worry about feeding them-they eat according to when they have to-they don't just gobble it all up like dogs and cats. So you can put a full bowl in the cage for several days, if you like. Get quite about a three/quarters of a metre cage for 1 rat, and a bit bigger for 2. Buy the rat a wheel, as they need constant exercise, and wood for them to chew on to wear their growing teeth down. Of course you can hold them and take the outside to play, but make sure that they can't escape or anything! Probably first time they will poop on you, so layer your hand with tissue and wear old clothes. But rats are more social than mice and will stop that habit in the end. You can't put a leash on them and walk them, but you can pop them inside a plastic ball (pretty hard to find in a pet shop though-still trying to get one...)and it can roll around inside it, going where ever they want to go. It's cool. Actually, there ARE rat leashes (look on google images), but you might step on the poor rat. You MUST handle them, at least a bit, because then they will never get used to you. They love playing, so they will allow lots of handling. They smell only if you don't clean the cage about once every week, or two times a week for males. If you are getting 2 and you think that 1 is going to get more attention than the other one, just hold them both-it's fun. They can eat fruit, so it can be their treats if you want. If you are only handling one and the other looks jealous, give it a treat. Have a great time with your rat/s!