The go-to slow motion plugin in many an editor's toolbox is RE:Vision Effects' Twixtor. Twixtor can often stretch a shot originally filmed at 30 or 60 frames per second into Matrix-like levels of slowness. However, the enterprising guys at Crumblepop have come up with a way of achieving this same effect using the Optical Flow filter that ships as part of Apple Motion. Here it is in action:
Pretty mind-blowing, right? Well, in addition to the tutorial below, they also pulled another ace out of their sleeve: the rain is added in post with Trapcode Particular 2. The droplets certainly help sell the effect, though the slow-motion alone -- considering it's being re-timed from 60fps footage -- is amazing. Here's another demo:
Okay, so how did they do it? Here's the tutorial for how to achieve this effect in Apple Motion.