This will be a prediction market that lets you bet on real-world events with reputation points (R) tied to your Facebook account. At the moment it's still in development, but you can sign in and make trades anyway. The current scores are provisional. At some point all accounts will reset to 1000 kR.

The rules:

1. Users trade shares in different outcomes of certain events.
2. Trading is denominated in reputation points (R) tied permanently to your Facebook account.
3. Users start with 1,000,000 R.
4. Each share is worth 1000 R if its corresponding outcome happens, and nothing otherwise.
5. Full sets of shares for every outcome of an event are bought and sold automatically for 1000 R when necessary. This means you can sell shares before you own any - the computer will buy a full set for you.

The ideas behind this website are partly from previous play-money prediction markets such as the Foresight Exchange, as well as a suggestion by Paul Christiano.