Banners
The following are various sites that I have found, and which are worthy of a banner advertisement. In essence, I fully sanction these sites, and I fully encourage you to go visit them and see what they're all about. They are listed alphabetically, in order to maintain an impartiality. Also, this page was first initiated on April 22, 2004, so likely the closer to that date we are, the fewer banners there will be. So keep checking back!

Celestia
is a free real-time space simulation that lets you experience our universe in
three dimensions. Unlike most planetarium software, Celestia doesn't confine you
to the surface of the Earth. You can travel throughout the solar system, to any
of over 100,000 stars, or even beyond the galaxy. All travel in Celestia is
seamless; the exponential zoom feature lets you explore space across a huge
range of scales, from galaxy clusters down to spacecraft only a few meters
across. A 'point-and-goto' interface makes it simple to navigate through the
universe to the object you want to visit

Orion's
Arm: Thousands of years in the future, civilization spans the stars, and
humanity has branched into myriad directions. Godlike ascended intelligences
rule vast interstellar empires, while lesser factions seek to carve out their
own dominions through intrigue and conquest. And beyond the safety of the
human-friendly worlds, adventure awaits those prepared to risk all.