I have been doing some research into the ASP.NET 2.0 Membership/Roles system. Community Server uses it, but I did not realize how many features it has right out of the box. I have been going over Scott Mitchell's series on the ASP.NET 2.0 Membership/Roles system and also Scott Allen's (when did he lose the 'K'?) articles. They have both ben helpful.
During my research I discovered the LoginView control. The LoginView control displays different content based on whether or not the user is logged in. You can drop this control right on the Community Server homepage and it seems to work great.