http://www.shatters.net/celestia/index.html If any webpage has ever been worthy of LotD status, it's this one. A free, 3-D view of the entire known universe. Look for amusing patches if you download.
Gil's LotD (Link of the Day) publishes a link to a web page every day. The linked pages are chosen for their interesting, informative or entertaining content. You can read Gil's LotD on the web or in a daily email.