The statistics of russian roulette are particularly interesting. If you were to play a single round (no pun indented), you have an 83.3% chance of surviving - not bad odds, everything considered. It isn't untill you decide to keep playing that things get silly.
Statistically - slightly depending on how the cylinder is spun, the design of the gun, and the weight of the cartridge, your chances might be different than 1/6.
Ways of spinning the cylinder, and their statistical effect on the outcome of the game
There are two main ways of spinning the cylinder before a game. On revolvers that have a cylinder that comes out on the side, it is possible to set the cylinder spinning, and then (with a Deer Hunter-style flick of the wrist) snap the cylinder into the gun. This result is most random, and the chances of getting a live round are indeed pretty exactly 1/6. The same goes for guns that break open along the axis of the barrel (imagine pointing the gun at a wall, and then break the barrel down, exposing the cylinder): Set the cylinder spinning and snap it upwards. Note that the person playing should never do the spinning themselves, as it is possible to catch a glimpse of the cartridge, completely spoiling the fun.
The second way of spinning the barrel is to close the gun, cock the hammer back half-way, and set it spinning. In some revolvers, you will have to halfway depress the trigger or release a catch to be able to revolve the cylinder without obstruction, while in other revolvers this will be completely impossible for mechanical reasons. The difference is that when spinning the cylinder in this fashion, the cylinder will be allowed to spin untill it stops. Because the firing cylinder is normally the one before the barrel (the action of a revolver, as you pull the trigger, is forwarding the cylinder 1/6th of a revolution, then release the hammer, firing the gun). However, as the cylinder has been allowed to churn itself to a stop, gravity will have had a say in the randomness of the stoppage: The bullet in one of the chambers will be inclined to liaison with gravity to stop towards the bottom, making it less likely to end up in the firing position.
It is possible - and this has no doubt happened in the past - that the person spinning the gun uses tricks such as the one mentioned above, to manipulate the outcome of the shooting, but that is a different matter altogether.
If you play consecutive games of roulette, including spinning the cylinder between each time, you have 5/6th of a chance of surviving every time - 83.3 %. Which, as we already established, doesn't sound so bad. But what happens if you keep going?
- After 1 game, you have 83.33% chance of still being alive
- After 2 games, you have 69.44% chance of still being alive
- After 3 games, you have 57.87% chance of still being alive
- After 4 games, you have 48.22% chance of still being alive
- After 5 games, you have 40.19% chance of still being alive
- After 10 games, you have 16.15% chance of still being alive
- After 20 games, you have 2.61% chance of still being alive
- After 50 games, you have 0.011% chance of still being alive
In other words: after 4 games, chances are less than 50/50 for still being alive. Perhaps it might be better to take a game of poker instead, in other words.
Oh, and remember to never play russian roulette with an semiautomatic pistol, as your odds of the gun not firing are somewhat lower and significantly less random than with a revolver.
Feel like trying the game but can't be bothered to die? I made a virtual russian roulette game, available here