Thanks, I've been working with the Hello example and I've read the docs and other posts here.

If I've got a form with 200 "theater seats" represented by image buttons, would you recommend building a "theater seat" user control and then placing them on a container form.  Or, would you have a user control that has the 200 buttons all using the same callback hander and passing the buttons' statuses in as a delimited string?

I think my newest module may be just what you're looking for. I call it "All Purpose AJAX". You can define a query and have the data automatically refresh to the screen using Jon's fabulous Client Callback API. It's template driven so you can display the data in any way you want. I've made some changes with 2.0. I've started using the DotNetNuke Scheduler to actually do the database access. The scheduled job retrieves the data and stores it in cache. The client callbacks pull the data from cache rather than making a database hit each time. This, of course, makes it MUCH more scalable and faster. Anyway, I think it's a good bargain because you get the source code for no extra cost. Here's the link for a demo:

http://www.bloodyflux.com/Products/Modules/BloodyfluxcomAllPurposeAJAX/tabid/117/Default.aspx

I think you can do exactly what you described with this module. All you have to do is define the query to pull the data you need and design a nice template. The module does all the AJAX for you.