i currently have two bettas, both sold as halfmoon doubletails (not entirely sure if this is what they actually are, though the petco here has employees who own/raise bettas and are fairly good at identifying them). their names are tailgate and knock out, after some of my favourite transformers.
tailgate's really nice and mellow, and likes to play tag with the tetras in his tank. knock out spends most of his time either racing round the tank or preening, so he's about the same as the robot he was named after.
'gate's got a bit of fin damage from when he moved into the 10gal a month ago, though it's been healing fairly well.