LevelTradingField.com has a parimutuel style bitcoin prediction system where users can predict the price of Bitcoin every hour. The Price is taken from the Chicago Mercantile Exchange's Bitcoin index BRTI. The BRTI is a average rate calculated from multiple exchanges.
Here is how it works. 10 people compete to predict the future price of Bitcoin at the end of the hour. They all put money in a pot. The person with the most accurate prediction gets 50% of the pot. the 2nd gets 30% and the 3rd gets 20%.
There are $5, $10,$20, $50 and $100 games. There are also free games running as well if you need to get some practice.
LevelTradingField.com has several tools to help with you prediction including charts, realtime Bitcoin Index prices and several statistics extracted from the ledger.
The games are pretty active these days.
Coindesk wrote an article on the game here: https://www.coindesk.com/game-skill-us- ... ting-game/