Odds/Probability I don't know the proper terminology but I would like to get a primer on odds and probability.  If the odds are set at 1 in 500 what is the probability of winning on the first try (0.02%?), after 500 total tries (the average would be 100%? but what are the odds of trying 500 times and still not wining), after 1000 tries etc.  I am trying to figure out if someone is unlucky and numerous people try 1000 times, how many people will still not have won.  Obviously, since each try is 1 in 500 there is a chance that someone could try infinity times and still not win.  I am just trying to figure out what the graph would look like.  I hope that makes sense.
Thanks in advance,
Jesse
 A: Sometimes "odds" is used as a synonym for probability. But that is technically wrong. If the odds of winning are $1$ to $500$, that means the probability of winning is $\frac{1}{501}$. 
If the probability of winning on any single trial is $p$, then the probability of not winning is $1-p$. The probability that we lose in $n$ consecutive (independent) trials is $(1-p)^n$. So the probability of at least one win is $1-(1-p)^n$.
Let $p=\frac{1}{501}$ and let $n=500$. Then (scientific calculator, or Google, or many online programs) $(1-p)^n\approx 0.368247$. So the probability of at least one win in $500$ trials is approximately $0.632$.
A similar calculation shows that the probability of at least one win in $1000$ trials is roughly $0.864$.
Remark: You mentioned that "the average should be $100\%$." That intuition, though technically not right, has a connection with the truth. If our probability of winning is $\frac{1}{500}$, then the mean (average) number of wins in $500$ trials is $1$. Sure, about $36.8\%$ of the time we don't win at all. But sometimes in $500$ trials we may have $2$ wins, or perhaps more. 
