We can add cool effects on our ubuntu desktop using compiz plugins, to install compiz on ubuntu all you have to do is open terminal/ console/ command line, and then run this:
sudo apt-get install compizconfig-settings-manager compiz-plugins-extra
Once installed, you can do many things with compiz, such as add rain effect, fire painting, wobbly windows, motion blur, 3D windows, cube reflection, etc.
But be careful, compiz may cause damage to your desktop, so make sure you know what you are doing and keep in mind that you can't activate all effect at the same time.
To open the compiz config setting manager (ccsm), simply search with keyword 'compiz' on your ubuntu dash.
Activate one of the effect, for example wobbly windows, enable it and then try open a new window and then drag the window up and down or left to right, the window should be bouncing around.