Rain. Pretty simple one. Just used a simple Max PFlow to do this rather than attempting anything too fancy. Tried to simulate water on the lense too. Rendered a sequence but not very happy with it. Some flickering and the overlay in front of the camera doesn't work too well. Also tried to fake the motion blur with scaled particles, but think this looks ropey. Too bright and in your face... but it took all night to render and these letters were supposed to be quick!
Here's a rendered sequence... meh