Well folks based on the good old free dictionary Wikipedia .......
Potluck dinners are often organized by religious or community groups, since they simplify the meal planning and distribute the costs among the participants. Smaller, more informal get-togethers with distributed food preparation may also be called potlucks. The only traditional rule is that each dish be large enough to be shared among a good portion (but not necessarily all) of the anticipated guests. In some cases each participant agrees ahead of time to bring a single course, and the result is a multi-course meal. Guests may bring in any form of food, ranging from the main course to desserts.
There you go.... hope it shed some light.
You may if you want, leave a comment on what you want to bring, (not necessarily food) but otherwise surprise us !