Making it easy to keep graphical applications running even if a server connection is lost or you simply wish to resume the application later, there is the XPRA project. XPRA allows dynamically detaching and reattaching to X11 applications without losing any program state. XPRA allows for remoting individual applications too rather than the entire desktop session.
XPRA isn't a brand new project but we haven't given it a shot out before on Phoronix. The project was hosted on Google Code but is now residing at XPRA.org.
The XPRA process runs on the remote host and allows session to be accessed over SSH or via TCP sockets while being optimized for bandwidth-constrained environments. Over the original Google Code version, the XPRA.org implementation has better performance, multi-user support, GUI tools/configuration, and other features.