Some of the comments in here have suggested that sports which require more thinking and less reacting are ideal, but in my experience, it's the opposite. I was the awkward child precisely because I spent too much time thinking about what I wanted my body to do, rather than trusting my body and letting it loose. It took playing sports where I didn't have time to think to snap me out of it. This isn't just something that helped me as a child, either. I took up roller skating at 25, and I was pretty awkward at it as most novices are, and I became a smooth skater by playing hockey, where I had too many other things to think about to worry about how to skate.
Gifted kids can be their own worst enemies in sports because they often think too much about how to move. Then they get labelled as non-athletic, and it becomes a destructive part of the self-identity. If they can get past that over-thinking, and with sufficient practice, there's a saying in sports where the game slows down for an athlete. That's shorthand for reaction times shortening, on the physical side due to muscle memory, and on the mental side due to pattern recognition and anticipation. That frees up a lot of brain power for advanced strategic thought... and it's at this point that the gifted kids start kicking the crap out of sometimes more physically-advanced counterparts.
