Our Little Monster

We have created a monster. I love my son dearly, and one of the cutest things that he does is come cuddle on the couch with us every night. The problem is that he comes downstairs repeatedly when he should be in bed sleeping. The kid has managed to stay up until almost 11 for 2 nights in a row now. Last night the only way to get him to go to sleep was to go lay in bed with him, but then I fell asleep also and woke up at 6am today in a race car bed. How do I get him to stay there without physically laying in bed with him until he falls asleep?