Installing and running games
Solution 1:
Not all games designed for Windows will run on Ubuntu. Some games will run on WINE, and some games need weird tricks or special treatments.
If you're having trouble running a game, search http://appdb.winehq.com for your game and see what others have said about it.
Here is the AppDB entry for Starcraft I: http://appdb.winehq.org/objectManager.php?sClass=application&iId=72
Starcraft II: http://appdb.winehq.org/objectManager.php?sClass=application&iId=11123
If you can't get your game to run, then you might also try running a copy of windows in VirtualBox (available in the Software Center). Though you won't be able to use the full potential of your hardware, so this won't be an option for playing any 3D games that are less than 5 years older than your computer.