Lots of people know who R2-D2 is, but few realize that R2 is actually an indicator for a whole bunch of astromech droids. For example, the Galactic Empire utilized tons of these droids for many different ships. These droids had the same basic shape as R2-D2, but had a different paint job and clearly worked for the Bad Guys™.
The most prominent example of these other R2 units is R2-Q5, and if you've ever wanted to see its shiny black exterior get the same attention as R2-D2, the folks at Sphero have something cool to show you.
While Sphero gets a lot of attention for its BB-8 and recently added BB-9E droids, the Sphero-made R2-D2 is truly in a class of its own. It's a tremendous accomplishment in realism, down to the lights in the dome and the behaviors programmed into the droid when connected to your phone. It's a quality piece of Star Wars gadgetry, and crazy fun to play with.
R2-Q5 is the "dark side" version, in much the same way that BB-9E is the darker form of BB-8. You have all of the same technical parts underneath, but the attitude and mannerisms of this droid will not be at all like you've seen from its infamous counterpart. If that's what you want in your collection, this option is now available to you.
Sphero is unveiling this droid at New York Comic Con today, with limited quantities for people in attendance to buy. If you're not there, pre-orders are up at Best Buy for $200