A space Invaders clone would probably be easier, as you don't have to worry about as indepth AI as there needs to be in pong, and the angle of reflection when the ball hits the paddle etc.
Also, If you wish to modify someone elses code, have a look at the examples that come with DarkBASIC itself, they are extremely handy.
Just try to learn the commands, and Impliment them one at a time.
For example, make a cube, then, make it move, then, make it controlable with the keyboard, then, make the camera follow it, etc. etc.
Hope I Helped...
Jess.

Team EOD :: Programmer/Logical Engineer/All-Round Nice Guy