I've done dealer's rooms, art shows, and been a guest speaker at many many cons, usually all at once, ribbons on ribbons, but I've never worked "concom" (Convention Committee). My friends have, though, and it is a lot of effort and planning behind the scenes to make a smooth event in front. I've shepherded my small CompuServe group for a decade at Origins, planning events, reserving dinners and such, and that is a lot more manageable than being responsible for an entire convention. My best advice would be to determine what you want to do (say... meeting room, art show, demo area) that way you'll know what sort of space and equipment you'll need (tables, comfy chairs, digital projectors, etc.), and then get the relevant advice from people who have worked various positions as concom. Somebody who has run a hospitality suite will know about the cost of food per person, somebody who has run an art show will know about protecting assets, someone will know about setting up registration, security, communications. You know from planning a party that a certain percentage of invitees won't be able to make it. If there is an empty place at the table, no big deal. If you are having catered lunches or renting a ballroom for the art show, there is more of a need to get a firm estimate of attendees. It is usually easier to expand if something turns out to be wildly popular. (And that makes great advertising, too!) :) Carolly