DevExpress has stepped up and offered to lead this open source project. In just a few short months, they have implemented a number of modern and strategic changes to the toolkit to help make it a valuable part of your ASP.NET Web Forms arsenal. This release is branded as version 15.1 and is available NOW from http://devexpress.com/ms-act
DevExpress has written a great post highlighting the updates they've made to the toolkit on their blog at https://community.devexpress.com/blogs/aspnet/archive/2015/03/10/announcing-the-asp-net-ajax-control-toolkit-v15-1.aspx