Because sometimes physics is really beautiful.
You have to love quantum mechanics!

These two sites comprise quite possibly the largest and
most succinct collection of mathematical and scientific
knowledge on the web!

Some NASA sponsored, beautiful pictures from the Hubble
Space Telescope.

A nice collection of photographic essays.

Every good nerd has some respect for irrational numbers, Pi
being one of supreme importance, a good site, fun, and
read about the PSLQ algorithm.