A easy way to run remote X programs (from another host) on your local linux installation is to connect to it via ssh using the -Y switch.
For instance if you would like to run up2date in graphical mode on a remote machine but the server doesn’t have X installed. Then this is a great way of doing it.
On your host
ssh -Y remote_machine_name.com
When you have successfully connected to the remote host you start the up2date command.
Soon after you will get the up2date windows on your local linux machine.
Your sshd server should have enabled the X11Forwarding directive. This is enabled in your local local machines ssh config /etc/ssh/sshd_config file
The command you run can be anything else, for instance xterm.