Conway's Game of Life
I suppose no science blog is complete without a reference to the cellular automaton known as Conway's Game of Life.
Wikipedia has an article that includes animated illustrations and a vast library of hyperlinks.
Can't get enough, can you? How about Eric Weisstein's "Treasure Trove of the Life Cellular Automaton," with plenty of animated GIFs.
p54 Shuttle, From Eric Weisstein's "Treasure Trove."
Interactive Physics Applets will BLOW YOUR MIND
Running a Windows machine or a reasonably fast Mac? Here is an astoundingly broad collection of interactive applets which demonstrate phenomena like: diffraction!, 3-D magnetic fields!, and other wild things.
Really, I mean it, this stuff will make you geek out like you've never geeked out before.
Paul Falstad's math, science, and engineering Java applets.
Like, try the "Ripple Tank Applet" and select "Zone Plate" using the Setup: pulldown in the upper right. Wow! So that's how Fresnel zone plates work!
Or try the "2D Wave Applet" and try "Setup: multiple slit" diffraction and play with the slit width and separation. What does it look like with polychromatic (multi-colored) light? Ever wonder why your credit card hologram is rainbow-y?
And don't even get me started on the 3-D magnetostatic fields applet...