Autodesk Motion FX is an effects plug-in for MacBook and iMac that works with the camera to give you some way-cool images. There's quite a bit built in to Motion FX, but the easiest way to learn what it does is to download it and play with it for 10 minutes. Do that and you might be hooked. Motion FX requires Mac OS X 10.7, so if you haven't upgraded yet this is a good reason to do it! Installation is easy.
To use Motion FX, you select an effect and it is applied to the image from your camera. You can see the effect onscreen with no delay. If you have face tracking turned on, Motion FX works with that to apply the effect specifically to faces. Even better, Motion FX lets you cycle through more than 80 effects, previewing each. There are some user-controlled effects for live video, where you can select specific colors or areas to trigger effects from. You can apply distortion to a live video feed from a mouse or other input device, too. A side-by-side comparison of original feed and feed with effect applied is included, which is useful. Most of the effects are similar, resembling smoke or fire from various parts of the image varying only by color and motion trigger, but there's enough variety to keep users amused.
While some users will treat Motion FX as simply a novelty app, when properly managed the effects can be attractive and worth saving. With it running on our MacBook Pro in a local coffee shop we always had a crowd of interested strangers gathered around, wanting to play with the effects. Motion FX is worth the download just to experiment with, and you may end up using it as part of your photo life. For others, it will be a cool toy for a little while.