An HTML5 sprite sheet animator: http://calhoun137.github.io/animator/
Animator is a handy web-app to help anyone who wants to quickly preview animation sequences using a sprite sheet.
There really isn't much to it, you just drap and drop an image into the giant grey box, and then set the number of frames in the X and Y directions, the time between each frame in milliseconds, and then you specify which frames to animate and click animate to watch the magic happen!
License: public domain.