I was lead here:
http://nuget.org/List/Packages/AjaxControlToolkit/4.1.50927
but I can find no download links. Where can I download this? I've already downloaded NuGet. Now what?
Nevermind. Once you install NuGet and it becomes integrated into VS2010, you right-click on the project and click Manage NuGet Packages. You then have to search for what you want and install it.