Some of my favorite online collections, any of which can keep you busy for hours.

Library of Congress

gutenberg project
...where you can find whole books that have been scanned and read or search them for free.

Darwin’s Correspondance
... I think I just really like the idea of all of any one person’s letters online and in a searchable database.

Hubble wallpaper
...some decently high res pics of space available to you, as they should be since it was your money that helped pay to create them.

more Hubble stuff

Nobel Prize site
...information on all of the Nobel prize winners, the most interesting thing is that they have recorded acceptance speeches from most of the winners that you can listen to.

more nasa stuff
...pics and movies from satallites covering all over the earth.

william gendey’s work
...a favorite of mine, this is a huge database of photographer’ William Gedney’s photos and journals.