You may notice In the later Ubuntu(and variants), that Glest can run extremely sluggish!
I have integrated graphics, I don't know about other people, so my graphics isn't that good without a good driver, and I ran into a solution, in about 2 minutes!
Solution:
Open the menu.
-Select the "Applications" tab.
--Select the "System" Submenu.
---Select the "Hardware Drivers" application.
It will ask you for the sudo password.
-Enter it.
--Select the "OK" button.
A window will open that says something like: "Scanning for available drivers that match your hardware".
-Wait until that window disappears, and then another window will pop up.
--The window will have a display of available drivers for your system, select the one that says recommended, if none say that, then select the one that looks the best.
---If the recommended one is already active, a green filled in circle will be next to it, if the circle is gray then it is not active.
----After you've selected a driver click "Activate".
-----After you click the activate button, it might tell you to restart your computer.
Restart your computer.
And............YOUR DONE!
Have fun playing Glest!