I heard about a local club holding a kermesse race, and I was wondering what exactly they were?
Not a big fan of this type of answer, but wikipedia has a pretty good definition of it.
The races are usually 90-140 kilometers in total length. While some are longer or shorter, most are about 120 kilometers. The race is comprised of a set distance and number of laps over the established course. There are typically 10 to 20 laps, of between 5 and 10 kilometers. The race usually begins and ends in the center of the town which is hosting the day's race. The race will occupy the roads in town as well as the roads surrounding, either city streets or farmland.
The course usually has a rolling enclosure. This means that while the race is not passing through, the streets are open to traffic. A designated car, usually with a caution sign and a red flag, leads the riders and close the cross streets to traffic. A following car, usually with signs and a green flag, open the streets back up to traffic.
The kermesse is similar to the criterium but differs primarily in total course length and lap length. While a criterium traditionally last 60-90 minutes, a kermesse will often take 120-180 minutes. A single lap in a criterium is usually less than 5 kilometers while the kermesse is usually 5-10 kilometers per lap.
See the link for info on payouts and UCI information.
The answer by domsterr is a really good summary of what a kermis is. Here's some additional info:
They have these almost every day in towns across Belgium (and Holland) through the cycling season. (I stayed in Gent and there was always one within 30k of there.) They begin at 3 usually. The top 20 pays. First place usually receives 150 Euros. On our team, as with others, the first place rider in addition to the winnings from the race got 200 Euros from the team. This money was explicitly for bargaining. Often these races come down to a small group of guys. At which point you have to be measurably stronger than your breakaway companions, or do some politicking. You can either pay off the guys in the break, or enough to have them work for you while you attack. This is always part of the racing. The guys who are strong enough just ride away, the rest pay off the guys in the break, then ride away.
The races begin with 40-150 guys and get whittled down to roughly 15. The guys at the front attack non-stop, each time whittling down the group. As the riders fall off, they are given a 1 lap to go warning and then they sprint for whatever place that is. The guys who actually finish kermis races, as in they last the entire race without getting pulled, are strong enough to race and win some PRO/1/2 races in the U.S. Often you will see national teams bring their riders to kermis races for training. Most national teams have bases in Belgium for the summer so their riders can race locally. Also, there are riders from professional development teams as well. Guys who are technically PRO, riding for a real team, but making no money. In one race I entered (I was always dropped very quickly) Iljo Keisse was racing--a track legend.
Here's my post from the first kermis I went to. The posts after this are all from ones I entered.
If you're interested in racing in Belgium let me know. I have friends there still and there's, no joke, a bike house where you can pay 200-300 Euros a month and race.