I've looked into the sugargliders in the past and although I really liked the animals themselves (check your local laws on these) I found a lot of the breeders to be total nut jobs. Several of them required a home visit to check out the living area before the sale. Several requested interview processes and follow up surveys/check ups.
For a rat with wings? Really? Whatever. If I'm jumping through those kind of hoops I'm getting a pet that can at least roll over on comand.
We've had gerbils, mice, hamsters, and guinea pigs. I liked our guinea pig the best. She would curl up under my wife's chin and chatter away contently.
Now if you're looking for
easy in the way of pets, and fun to watch I'd go with hermit crabs. I've had them on and off since I was a kid and they are very easy to take care of. They don't require a lot of attention, and mainly like to come out at night to explore and knock around.
Neat to watch.