Some very useful AJAX controls
Nikhil has written a couple of great sample controls located here. The controls are UpdateHistory and AnimatedUpdatePanel. The UpdateHistory allows you to add navigation history / bookmarks to AJAX navigation where it makes sense such as when drilling in to a details view from a high-level view on the same page via AJAX. The AnimatedUpdatePanel provides a visual cue while the UpdatePanel is, well, updating:-) Read Nikhil's blog for more background.