»Have everyone involved in the inviting submit a list of the people they'd like to attend. They should rank the names in order of importance, starting at the top.

»Compare the lists and cross off any duplications.

»Add up the names that are left and compare that number with your goal.

»If your count is over the limit, determine how many names you need to eliminate.

»Then, have each person cut an assigned number of names, starting from the bottom of his or her personal list.

Not inviting children can be an efficient way to eliminate an entire block of guests, and though some parents may be offended, they shouldn't expect you to invite their kids. (Just be sure to apply the decision uniformly, and don't make exceptions.)