What is this hand game (like RPS), and what's a good strategy?

[fatdave]

What's this game where two people throw out their hand and point out one, two or three fingers against the other person. What are the rules of this game?

I assume that it's a lot like RPS, and the odds are pretty much 50/50 unless you notice a definitely long-term pattern... am I wrong? What's a good strategy?

What are some other RPS-like games?