Sandboxing Applications with Sandboxie

Sandboxing is a security mechanism where applications can be isolated and activities can be restricted. I find Sandboxie the most effective application to provide sandboxing. I have tried many free alternatives, but they were not able to support all applications. The first sandboxing application I know is GreenBorder which was founded in 2001 then bought by Google in 2007. There's already some speculations that GreenBorder will be integrated with Google Chrome. Other alternatives include Returnil and Comodo Time Machine. What can we do with these apps?