Sleep walkers

For the last couple of weeks both boys have been getting up during the night and coming to our room. I know that some people like to cuddle in bed with their kids but I'm not one of them. My boys flop all around, whack you in the face, and nearly push you off the bed. Not fun to sleep with. Luckily, we never had a huge problem with them sleeping in their own beds, even when they first came home (other than about two weeks). Alex usually comes around the same time - 5:30 am. Zachary comes at all hours, midnight, 4:30, whenever. They climb up Chris's side of the bed and crawl over him to get in the middle. I immediately scoop them up and carry them back to their own beds and they stay there. I don't know why they've started doing it. They don't say anything and they don't cry. I do now wonder though - should I take them to the potty when they get up? Could that be what woke them up? Any ideas?