This is useful for educational purposes, too - wirelessly streaming from a chrome browser or chromebook to a projector (via hdmi to vga adapter).

(An alternative if you have a laptop connected to the projector is to run AirServer to act as a virtual Apple TV, and then either airplay from your ipad or run AirParrot from a windows tablet. Of course Chromecast will be the first solution to work from android tablets, too, since Miracast solutions still seem to be non-existent or not so great.)