Re: An interesting alternate to HAP?
Interesting adaptations. I would like to see the code for your generator, Lemming.
The problem, of course, is that the numbers at the ends of the range occur so seldom that it is going to be a looong time before the row or column they are in can be completed (a '3' for example, occurs once in 218 permutations), while other values occur so often that many rolls will not be able to cross off anything on the card.
If you look at the example pages, they use a 5x5 grid (headed by K - A - R - M - A to maintain the BINGO analogue) and some numbers occur more than once in the grid. I assume that you can only mark off one square on the grid at a time, no matter how many times a value occurs. They also (in their usage example) show that a player is playing all 4 of the grids on the page, not just one (again, much like many BINGO games).
As for generating your own grid; It might be more 'fair' to randomize 25 values out of the 218 element permutation space. You could even generate 4 grids at a time by randomizing 100 out of 218. I will think on this a bit...