When looking for a good program in Ubuntu Software Center, we may be obliged to install/remove many programs until we find the desired one. If you wish to avoid filling your hard disk with unnecessary files left by removed programs, you can simply test the program without installing it with the help of QTNX, which is a client for NX remote desktop.
To install QTNX on Ubuntu 12.04/11.10 or older, run this command from the terminal:
sudo apt-get install qtnx
Start now Ubuntu Software Center and open any application. You will notice that a button labeled "Test drive" is added under the application's screenshot:
Click it, select a distribution and click OK:
A window will pop-up which will install and run your application in a remote server without touching your local hard drive:
You should know that not all programs are supported by this option.