When Bitcoin will reach $100.000 or any exact price you want.
Futuur already have crypto related betting markets. Like this one:
Will Bitcoin’s price surpass $100,000 at any point in 2021?Don't involved this forum for betting since it's high potential to be cheated (e.g. merit trading, spam, create a bunch accounts etc). It's not for predict, but it should to be a celebrations.
So there is no way to make any fair betting market which will be related to bitcointalk forum? They have pretty low betting limit now. As a result the winning amount won't be very high. You can highly get around $30(0.0006 BTC) profit by placing bets on any market. Although it may change by little, but do you think that people will cheat by creating thousands of account for the small profit?