I've been gathering a list of custom actions for a while.
A custom action can really be just about any “link” on the internet that you want to send people to, but often new viral marketing people need a kick in the brains to realize the power of custom actions.
So this list, is your kick in the brains.
Oh, and let me know when you come up with one that isn't on the list! I'll add it and give you credit for the idea!
For a bit more info on custom actions:
And if you want a LOT more (long winded) info: