Design Patterns for Games Theory

[jrws]

Hey guys,

I have been programming for a while and I want to know what sort of design patterns I should look into when making a game?

For example what design pattern is best for:

Database management

User management

Forum management

Etc

I can only think of singleton or factory (for user/forum)

I am reasonably new to OOP, but would like to learn it properly, so I thought creating a simple program such as rock-paper-siccors would work to be able to expand it eventually, and hopefully it will teach me reusable code practice.