I was running through my list of blogs and I ran into "Create a Facebook-like Ajax Image Gallery!" by John Katsiotis. In John's post he shows how to create an image gallery - it's quick and easy - but more importantly he utilizes the new ASP.NET AJAX History feature. That means you can use the back and forward buttons on your browser to go back and forward through the AJAX calls.
And on another note, LessThanDot has published a collection of ASP.NET Hacks in 18 categories (currently) including: Caching, Email, Encryption, Validation, Files and others.