Last weekend we watched a friends' son for the weekend. It was the first time we attempted overnight babysitting. I have to admit, I was a little leery of the situation given that watching my own child all day at 8+ months pregnant has me ready for bed at 6pm.
It was definitely a challenge to make sure two two-year-olds had everything they needed (essentially two of everything) everywhere went. And an even bigger challenge to mediate play time since anytime one kid touched something, the other immediately wanted it and we only have one of most of our toys... MiniM.E. was really into helping to babysit our visiting toddler, but like most two year olds, he wanted to do everything himself- not have MiniM.E. do it for him.
Overall though, they both seemed to enjoy having a permanent playmate for a couple days.