ComfortASP.NET: AJAX-like programming in ASP.NET
The ComfortASP.NET projrect is interesting: http://www.daniel-zeiss.de/ComfortASP/
It's an attempt at bringing enhanced client-side functionality to server-side web applications, without forcing a developer to use technologies like DHTML, AJAX, remote scripting, or JavaScript. I'm still not quite sure what it is (a library, it seems), but it's a neat idea.