I help run the Poker Society at my Uni and what we did (and are going to do) is draw a random number (which corresponds to the number of runners) and that person gets there money back.

Its only a £5 buy in FO - it didnt affect play at all - the first time we did it, the number was second to last - the game was still pretty tight.

We did it just to add an element of "fun" into it - hopefully it will keep people coming back - its not supposed to be 100% serious - a social event more than anything.