The Delta Clipper program is history now, due to the unfortunate landing accident after a test flight July 31. However, a record of its flights and its impact on future launch vehicle development lives on at the Delta Clipper Experimental Archive. This site has a wealth of information, including lots of images, from the DC-X/DC-XA test flights.

http://www.engineering.usu.edu/Departments/mae/Space/dcxa.html

This is a detailed simulation of future models of human growth across the solar system, inspired by Marshall Savage's The Millenial Project. Explore previously-run simulations of human expansion or create your own. There's a Java applet version of Solarpop that allows easy-to-use dynamic control of new simulations. The wealth of detail in this site is amazing!

http://www.millennial.org/~ccleave/solarpop/

Astronomer Dr. Sten Odenwald answers astronomy questions... lots of them. Ask him a question at The Astronomy Cafe and he'll reply within a few days. The questions range from very basic to deep philosophical topics, although the most popular question is "How long are you going to keep doing this?" Also check out the articles and other resources on the site.

http://www2.ari.net/home/odenwald/cafe.html