When you have a lot of controllers, you need to organize them under Namespaces. Also, it is better to put controllers under subfolders in order to organize them properly and have some meaningful URL for them like /Admin/User where Admin is the subfolder...
UFrame combines the goodness of UpdatePanel and IFRAME in a cross browser and cross platform solution. It allows a DIV to behave like an IFRAME loading content from any page either static or dynamic. It can load pages having both inline and external Javascript...