Distributes people in various slots maximizing the global satisfaction, taking into account quotas for each slot.
Organize the groups for various activities according to the desires of your friends, prepare the schedule of an oral exam taking into account the wishes of the students, plan who does what in the organization of a party,...
If you are using Wish for the first time, you might want to take a look at the help page.
If you don't need to contact the participants by email you can use the offline version.