This afternoon, Johnny rode a two-wheeled bike for the first time!  His training wheels are all mangled from dropping the bike on it's side (to be fair, they were messed up even when we bought the bike), so I took them off and told him he was going to ride without them. 

It took about 15 minutes (~10 laps around the cul-de-sac), and he was off!  I was going through the whole “pretend to hold onto the seat” thing, thinking he would worry if I let go.  I had Steph take some laps with him, and she just jogged alongside him...he didn't care at all. 

So far, only one significant crash, but it didn't slow him down much.  Now he wants to practice "taking off" by himself, so he can be totally independent.