This is one of those things that is simply sweeeet! In-camera 120fps just opens the door to so many cool stuff!

Gopro HD HERO2 in slow motion 120fps mode (0:30) by powerlord69

Here’s a quick one shot in 120fps mode. Playing back at 30fps (25% speed). I then slow the middle bit down to 6% speed with Final Cut Pro (optical flow).