There's probably more sophisticated freeware out there for Windows.
-MilesAhead
Lots of freeware for Windows out there but I couldn't find any for real-time video... just pre-recorded stuff.
I did read about one that flips a video, plays the frames in reverse order, from the end to the beginning. Who the hell would want that? 
-crabby3
That reminds me of a regular feature on the old Steve Allen Show. He would do some stupid stuff, like slide down a rope, shoot arrows into a target, break a dozen eggs, throw jugglers pins behind his back into a basket etc.. then play the film backwards. The pins would jump out of the basket into his hand behind his back, eggs come together, arrows jump from target to the bow, then he'd put them in the quiver... when done he slid up the rope. Pretty cool because he always had in mind how it would look backwards.
Read your profile but I couldn't tell if you're old enough to know who Steve Allen was.
