[F8] Games: Making the difficulty Increase

I have searched the forums, have not found anything. Hopefully this hasn’t been posted before. If it has, I am truely sorry.

Anyways…

This has really bothered me. I cannot find a good algorithm (If there is one) for increasing the difficulty of a game. For example, a game where you have a bucket and you have to catch balls that fall. What would be a good algorithm to make the difficulty increase over time?

Thanks in advance,
Jon

EDIT: Darn! Wrong forum, please move.