"I've had my fair share of fun. I tried acid, once. But I think it had been watered down or something. So it wasn't, apparently, what it was supposed to have been. But I do remember lying outside in Mexico, where it happened. There was a tree outside and suddenly the limbs of the tree became frogs hanging upside down. That was, understandably, the last time I did that." Neil Patrick Harris has dabbled with drugs - and vowed never to do it again.