The problem is that... well, Mark really likes underpants. He figured out pretty quickly that if he pees in his underpants, he gets to pick out a new pair. And we're not talking about a little bit of pee. We'd turn around to find him standing in a pee puddle 4 feet in diameter.
So we tried some other incentives/penalties:
1. If you tinkle in your underpants, you don't get to pick out new underpants until tomorrow and we'll wear a diaper for the rest of the day. Mark's response: It's OK, I got tired of using the potty today anyway.

2. We'll give you an M&M every time you make a tinkle in the potty. Mark's response, after the first 2 M&Ms: No thank you, I don't want any more M&Ms.
Then Matt had a genius idea. He tried: Mark, if you make it all the way until bedtime with dry underpants, I will give you your very own baseball card. We can make a special box for you, and you can put a card in there for every day you keep your underpants dry.
As it turns out, Mark likes baseball cards even more than he likes underpants. It was like flipping a switch.
So far, he's made it 6 days without any accidents. He's been to the Children's Museum and Brookfield Zoo in his underpants, both without incident (other than visiting the bathroom roughly 400 times). He's made several long drives in the car without soaking the seat. We haven't gotten rid of the diapers at bedtime yet, but so far he's telling us (with approximately 2 minutes warning) before he has a potty emergency. Pretty good, we think.
Matt says this experience should teach us all how valuable baseball cards really are. To that Lynne adds: to little boys.
