From what I understand there was rampant betting before the Trinity Test, about various outcomes.
Some scientists present were concerned that Trinity would set off a chain reaction, igniting the entire earth's atmosphere. Fortunately, that didn't happen. But it would be hard to collect on a bet aftewards...
Yeah, there was. Some of the more interesting bets were whether or not it would ignite the atmosphere or blow a hole down to the center of the Earth. A lot of the weird bets are often attributed to Edward Teller but it isn't known whether or not he was responsible for all of them.
Teller was known to be a joker. Just before the test, he was putting on sun screen.