Make a Casino, run a lottery, ect.
Seriously, just stack up the odds of winning such that there is a 1 in 10000000000000000000000 chance that someone will win, then offer 1 Billion dollars as the prize. If you tour around some trailer parks you are almost guaranteed to make a small fortune. (You could win 1 Billion dollars, all you have to do is guess 27 of the 30 digits that I will randomly generate!)