Five Acres with a View

Pulsate is a strange little Flash application that plays random tones in response to circles that you draw on the screen.  Draw at least two circles (but more is even better) to hear the sounds.  Press the space bar to clear the slate.

Physics Games has games based on physics. One of them, 99 Bricks, is a Tetris variant.

People blow smoke rings:  Dolphins blow Bubble Rings. (via Pharyngula.)

This flash application shows a panorama of a fabulous library.