There is a popular form of market on manifold, with something isomorphic to "Will this market close above 50%".

In theory, this is the nicest possible market, it it always resolves in the direction of highest net gain. However, there are two major issues with this market.

First, it is very common for someone to enter the market right before it closes to be the last to influence the market resolution.

And the other issue is that people betting large amounts of mana ("whales") are heavily over-represented. So this market will focus on resolving these issues.

For the whale problem, for this market, only the square root of your position will count. For example, a user with 10,000 YES shares will contribute 100 points to the YES side. The side with the most total points will be the side that it resolves to. This will make it much more difficult for one "whale" to control the market.

For the first problem, after the market closes, a random integer N from 0 to 100 will be rolled, and trades made within the last N hours before the closing time will not be considered in the resolution. This will prevent it from getting sniped.