Hey, we discussed building a collection of controls/helper methods that we as a user group can work on.
I've setup a codeplex and started hacking on a few generic controls:
http://www.codeplex.com/udnug
Right now it has 2 controls, a CheckBoxListExtender that allows you to define a minimum and a maximum amount of selections on a checkbox list, and a BaseValidatorStylerExtender that allows you to define a control to style with a different css class when a validator is invalid, this allows you to define a label to style when a textbox input is invalid.