Compoundle

Compoundle comes from O'Flaherty Bros. Games. Each day's case is a mystery stock: a real company frozen at a date in its history, with the financial figures and context you would have seen then, but not its name. You pick an amount, then choose Invest if you think the stock went up, Short if you think it fell, or Pass if you would rather stay out.

When you reveal the result, the game shows the company and how its share price moved, and applies your gain or loss to a running balance. That balance is ranked on a global leaderboard, so a single bold call can move you a long way up or down. A daily cash drop grows if you come back day after day to keep a streak.

The case calendar is shared by everyone and changes at midnight Mountain Time. Arrows beside the date take you back to earlier days' cases, and an Advanced metrics panel, a stock movement chart and five years of financial reports add detail for those who want to dig in. The site warns that it is not investment advice. Accounts are optional but keep your balance across devices. It suits people who follow markets or business history and like to test their judgement with stakes, even pretend ones.