Party in my crib... 3 AM!!!

Have you seen those pajamas for babies?
This seems to be the invitation that Sawyer's been sending out to his imaginary friends for the last few nights.
He's been awake from about 2 to 4 AM for four out of the past five nights or so. Just talking to himself, entertaining himself, crying a little here and there -apparently just to make sure we're still around, cuz he doesn't really want us to help him get back to sleep. It's driving me nuts. He's not hungry, he's not too warm or too cold, I don't think he's in pain... I just don't know what his deal is. We've tried ignoring him; it seems like he'd just stay in there awake all night that way. We've tried rocking him for a bit, patting him in his bed for a bit; then he just wants to play.
So last night I was awake later than usual, (I wasn't having any luck sleeping which is why I had to get that Some People rant out of my head...) and I heard Sawyer in his room a little after midnight. At first I just thought he was making sleeping sighs and noises or maybe talking in his sleep. But I went to listen at his door and realized he was most definitely awake. He was in there talking to himself, jumping in his crib, singing a little, and I even heard him yawn. So I went in to tuck him back in, give him a little pat, and hoped he'd go back to sleep. He was still awake when I went to bed at 1:45. I tried to go to sleep, but I couldn't fall asleep becuase I could hear him on the other side of the wall. He finally started fussing about 2:30. So I went in to try again. I think I finally stopped hearing him babbling and shaking his crib by about 3 AM.
This morning I got to thinking, he was so content in there to talk to himself and play in his bed for almost 2 hours before he started fussing for us. What if he's been doing that every night? What if he wakes up and talks to and entertains himself for quite awhile before he finally decides to let us know he's awake and bored in there? So while we think he's been awake for an hour or two, it's really like three or more??? What is up with this kid?
All I know is he'd better get his scheduled straightened out, or I'm moving his bedroom futher down the hall so I don't have to try to sleep with my head on the other side of the wall from his little all nighters!

Did I mention there were two days this week that this little man decided to only take one nap all day?! He must just be on a sleep boycott or something.