Yes, twice.
First time, sometime last year I think, I met up with an online friend I'd had for years (he's from Canada, I was in Texas)... In Florida. We just so happened to be in the same city at the same time, despite living vast distances away from it. So we spent the day at LEGOLAND Florida and ate pizza and stuff. It was awesome.
Second time, earlier this year, I met with another online friend from LEGO Universe at Destiny USA in New York. We got some food, walked around, and went on the world's largest indoor suspended ropes course. Again, quite a lot of fun.
I've also had the reverse happen to me... I met a guy in an orchestra I played in years ago, we were stand partners, then I moved and we lost contact. Years later, he was watching some LEGO Universe videos, found some videos I had uploaded, recognized my voice, and tracked me down in-game, just days before the game's servers were permanently shut down. We talk on Skype now and stuff.
