A Consuite is one or more rooms that are devoted to providing hospitality to the convention's members, usually in the form of food and drink and space for good conversations.
Typically conventions provide both a non-smoking and a Smoking Consuite.
Sometimes the con suite is used before the con for a Welcome party or after the con for a Dead Dog party.
See Regional Variation below as ConSuites are by no means standard at non-North American conventions.
Planning and Executing a Consuite
Food and Drink
A ConSuite is expected to have a certain minimum in food and drink - at the very least, salty crunchy things and something to wet your throat. When you're doing your menu planning you have a lot of factors to consider, including size of the convention, budget, local law, your hotel contract, and your convention's traditions and values.
If you have a multi-day Con Suite and buy all supplies in advance, you would do well to use part of your set up time to subdivide your supplies by days, with the bulk in a peak day(s) of the convention. Also, store your supplies in a private area (under table drapes, in the closet, in another room) so attendees don't just help themselves and leave you short later in the convention. Make sure staff knows to only put out supplies from a particular day.
There is a magical art to planning the layout of a ConSuite. You have two main goals: support the flow of traffic through any area that is serving food and drink, and support the existence of eddies where people might stop, relax, and converse. Do one without the other and you have something suboptimal.
When submitting the layout to the hotel, ask for extra tablecloths so you can swap them out as they get dirty.
Themes and Other Decor
If your convention has a theme you may wish to carry it through in the decor of the consuite. Or each room could have a different decor, each night could change with the theme of the party, etc. In any of these approaches, planning ahead is a good idea.
Staffing and Schedules
It is best to plan to have a staff member -- a trained, knowledgable volunteer, who knows what's going on -- present in the consuite at all times. You can supplement this staff member with gophers, and in a minimal consuite you may not need them at all, but unltimately, your staff are your saviors. Because really, you do need to sleep.
Post the staffing schedule in your prep area and give both your staff and Ops a copy of this schedule and of your contact information. You should also have a menu schedule posted in the prep area so people coming onto shift know what to put out.
Regional Variation and Genre Variations
When you're planning how to run a Consuite, and observing how other people run them, you will rapidly realise that there are regional, international, and genre variations. Some of this is due to culture and architecture, some of it to law, and some simply to Tradition.
In the UK, for example, a hotel might have a pub that has rather a family atmosphere. However it is far more common that a hotel will have a bar that is open to all hotel residents (and the general public) which convention members can use, and often one or more bars that are opened exclusively for convention members. It is very unusual for "free" food or drink to be provided at UK cons, though often there will be an arrangement with the hotel to provide cheaper meals and discounted drinks. It is common for the convention to work with the hotel in providing "Real Ale" (better quality bitter beer from a quality brewery) for the attendees. This Real Ale is still sold by the hotel and not given away free. A typical UK pint will cost around $5-$6.
Filk Conventions often have quite elaborate con suites, including a wide variety of foods, a computer for internet access, etc. This is possible because Filk Cons usually do not have the huge attendance figures that Gen Cons or Star Trek cons do. This frees up the staff to be more creative (when you don't have to carry a 5 ton trucks worth of beer into the con suite, you can use the time for other things).
Some conventions serve alcohol, others do not. As far as I recall, it is more common to find beer in the consuite in a Midwestern con than at one on the coasts. You should do well to find out what previous consuite heads before you have done for your convention, not only to make your planning easier but also to make sure you aren't skipping anything that fans steeped in the "Tradition" of last year might kvetch as you about.
Another variation is in time schedules. Many conventions maintain a 24-hour ConSuite. You do not have to do this. Many conventions don't. But ConSuites that at least run late into the night are one of the many ways SF conventions stand out from other types of events.