My 4-year-old (5 in February) asked us outright this year, "Is Santa real?" We did our typical, "What do *you* think?" thing and sort of avoided answering (we weren't really ready to be done with it, to be honest). He told us later that he didn't think Santa was real, but once it came down to Christmas Eve or the day before, he totally got into leaving cookies and milk for Santa, and the whole bit. Christmas morning, I think he was just excited and not asking any questions.

He was at an event with a "Santa," and he sat on his lap and played along, but he didn't feel the need to ask Santa for anything--although he did make sure he mentioned to his dad and I some of the things he'd like.

When we asked him about it, he said, "If Santa really wants to get me something, he can surprise me."
Anyway, I don't think he *really* believes Santa is real at this point, but he seems happy to just sort of go along with the fun for now.