Hey, Scripting Guy! How Can I Add a User to Multiple Groups?

Hey Scripting Guy! It seems that I can never find what I need anymore. I am looking for a Windows PowerShell script that will add a user to multiple groups. The user and the group are in the same organizational unit, and I do not want to have to run the same script multiple times to add a user to multiple groups. It should be easy to do, right?-- W...