At work we are running a Bingo game for United Way charity in which we purchased 3 cards for about $5 and the winner splits the total collection in half with the charity. Numbers are picked by a program and put on our corporate intranet site and I currently need 3 numbers for a full clear to win.
Or this, based on a choose formula of C(5, 15)xC(5, 15)xC(4, 15)xC(5, 15)xC(5,15) you have a total 111,007,923,832,370,565 possible winning card combinations. C(5, 15) is 3,003 possible combinations for a single column.
I was about to figure out my rough odds of winning based on the fact that 58/75 numbers have been drawn (find out the number drawn from each column and the number left in each column, etc) but when I started to think about it I realized I don't really care that much and I should probably do actual work today. But heck it was fun thinking about it.
I also invented the concept of a Super Bingo that uses unique permutations instead of just combinations, meaning that 5 bingo cards with the exact same numbers would not all be winners at the same time. So you would be drawing B-(3)-10, meaning Column B, Row 3, number 10. This could work for World Bingo events where the number of possible participants warrants a greater number of possible combinations.
Now I know why all those old folks like bingo so much, they must be doing the math while they blot away!