It looks like Microsoft’s Arc Touch Mouse is real. Images have leaked from a German online store that show the mouse, with some specs too. The main draw here is the curved design, which provides more ergonomic comfort, and the mouse also folds down for portability.
Other features include touch-scrolling, multi-surface tracking, a battery indicator, and 2.4GHz nano receiver. The price is in the neighborhood of $70, but availability in the U.S. is questionable at launch.