Well, they’re not quite like what we see on Star Trek, but "ray guns" are here.

Right now, firing rays requires a dish antenna mounted on the back of a small humvee.  Although the rays can reach a distance of 500 yards (17 times the range of most bullets), they don’t actually kill anything.  In fact, all they do is project an invisible beam "intense enough to make participants think their clothes were about to ignite" and, presumably, drop their weapons, or disperse, or whatever.  It can penetrate clothes.

Oh, look.  I found a diagram:

The name for this ray gun is rather lame: The Active Denial System.  Dumb.  It sounds like it’s something that comes from Batman’s utility belt.

The military will start getting this stuff in 2010.  More here.