Many times I have used the flip of a coin to end an argument, and in respect how fair in chance really is such events. Say you wanted to make some random engine that would generate some outcome entirely of chance? With the lottery I do not think its hard to see the pattern, as I think most of its probability is based primarily on population density really of say each ticket. Plus its related to say such a thing staying alive, obviously as if each ticket out of two purchased was worth say 100,000 dollars greenback the system would fail. So probability is controlled really. So back to my coin flip, that is more or less somewhat different physical phenomena related to probability, such as just the flip motion, how its caught, the coins energy, etc…

 

How do you make something that is truly random, even if you had a billion sided die, if you rolled it for long enough would not the fact it has only a billion sides lead to eventual bounds on the probability? So what could you do to make probability limitless or infinite?

Thermal noise in electrical components.

In addition to what swansont said, some information can be found here. I remember how a couple of years back I started thinking it would be cool to have some sort of microchip or a small module that produces truly random signals based on some nifty quantum phenomenon and later realized there were actually lots of techniques to achieve this already. Of course, when talking cryptography etc. it's worth noting that many components are vulnerable to attacks (especially the thermal components), and that the randomness decreases over time as entropy increases. Apparently the latter can be countered somewhat with estimations about entropy progression though. But yeah, these kind of components and mechanisms are the way to go for any purpose that requires true randomness.