The idea is inspired from and depends on @Spook's idea - "Personal bet mediation service"
The idea is to bet on what will happen in the future. For example, a person can predict a date when the first human will land on Mars. Others can then jump in and bet on the same or other dates. They pledge money towards their bets and a person or a few people win in the end. Each bet can have a different set of clauses. For example, a certain thing that is bet upon may or may not happen, like aliens landing on Earth. Therefore, every bet has to be placed with an expiry. The conditions for the return of the winnings in such a case need to be decided while placing the bet. When another user wants to bet against it, they need to accept all the clauses in the bet. If they are not comfortable with some of the clauses, they may suggest amendments but the person who places the first gets to decide whether to accept or reject the suggestions. The bet mediation will be as Spook has described it in his session.
Since users will bet on things in the distant future, there needs to be a dormancy period. Bets that may expire in the near future should be discouraged. For example, you may not be allowed to bet on the amount of snowfall New York receives in January, 2022; it should be more like January 2032.
This is the best part - the people who place bets on a certain event get to decide what happens to the money until the bet expires. They may invest it in different funds or companies or keep it in the bank. The betting may, thus, act as a passive stream of income for the users.
Initially, I imagined this to be a fun game where the wagers are minuscule (up to $100). However, this can be a serious source of income for futurists.