Warren,
Please check the following examples:
11. Ajax based user profile
User profile is the primary part of a community application. Ever wanted to allow users update the images of their profiles using AJAX without reloading the page? Check it now!
8. Simulate File Upload
A sample demonstrates how to use .Upload method to simulate a file upload event.
asp.net Chat http://cutesoft.net/ASP.NET+Chat/default.aspx
Web Messenger: http://cutesoft.net/Web-Messenger/default.aspx
asp.net wysiwyg editor: http://cutesoft.net/ASP.NET+WYSIWYG+Editor/default.aspx
asp wysiwyg html editor: http://cutesoft.net/ASP
asp.net Image Gallery: http://cutesoft.net/ASP.NET+Image+Gallery/default.aspx
Live Support: http://cutesoft.net/live-support/default.aspx