I'm pretty sure it's called a Drop-in bar made by Scott. It was meant to add another hand position option, but many riders (including me) found it a little too awkward/uncomfortable to use. I imagine anyone coming from a flat bar (mtb or hybrid) background would like it since you can get aero and still have your hands in the tops orientation.

edit: ruppster beat me to it. Did you use altavista to find that pic? It was the first one to come up in my search.