About the SCA
SCA stands for "Society for Creative Anachronism," which is a fancy way of saying we're a group of people who explore pre-1600 cultures through re-creation rather than just studying; sort of like a hands-on version of Medieval History 101. (Most of our focus is on European cultures post-CE, but not all!) It's often said that "if they did it in the Middle Ages, someone in the SCA has tried it!" - and that's probably true. Martial activities, costuming, cooking, needlework, animal husbandry, weaving, beadmaking, lacemaking, leatherwork, carpentry - the SCA has something for everyone!
The SCA is organized geographically; the world is divided into several Kingdoms, which are further subdivided into smaller groups (e.g. Baronies, Shires) which are themselves often further subdivided. (In other words, even if you're not local to Buckston-on-Eno, there's probably a group near you!) While the SCA does offer paid memberships, you don't need one in order to participate.
Kingdoms are ruled by a King and Queen, one of whom has won the title in a tournament. Unlike the Middle Ages, our monarchs have term limits - and that's more for their benefit, since serving as King and Queen, while fun and rewarding, can also be a highly stressful (not to mention expensive) experience. Also, our monarchs don't rule with absolute power; in fact, it's probably fair to say that they have political influence rather than actual power. The SCA is 'ruled' by a Board of Directors (BoD), whose members are nominated and commented upon by SCA members before being selected (by the seated BoD) for appointment.
As members of the Society, we pursue a lot of medieval activities at home in our spare time. In order to see what other people are up to, show off our handiwork and generally immerse ourselves in the Current Middle Ages, we hold 'events' - day or weekend-long gatherings hosted by an individual group. These events may have particular themes, e.g. a particular time or culture, a particular craft or activity, etc. People come from across the Kingdom for these gatherings; depending on how far you're willing to drive, you could probably go to an event every weekend! The only thing required to participate in an event is payment of the entrance fee (usually very minimal; just enough to cover building rental costs) and an attempt at pre-17th century clothing.
What to Expect at Local Meetings
Local weekly meetings, at least in Buckston, have a number of parts. We often have fighting practice; we sometimes have dance practice; we'll sometimes have someone teach a class. In general, though, the purpose of the meeting is the business side of running the SCA. Sometimes this is minimal; other times (such as when we're making plans for an event we'd like to host), it's much more involved. Many groups, Buckston included, often go out for dinner and socializing after meeting - after all, the main point of the SCA is to have a good time!
Basic Kit means something to wear and (usually) something to eat off of. Easy enough, right?
Participation in an SCA event requires an attempt at pre-17th century clothing. Note the word attempt. This means you make an effort. It does not mean your garb has to be painstakingly researched; it does not not mean you have to make it yourself; it does not mean it has to be particularly pretty. (If it is all of these things, and you have a good time: great! But attempt really does just mean 'attempt'.)
A personal note from the webminister: I highly recommend waiting a while before you create your own first garb, or at least before you put together something you're really excited about. Borrow from your group's loaner gear or from friends, or wear something less than perfect for a while. It takes a while for you to get a sense of what's out there, what you want, and how you want to get it (particularly if you don't want to sew it yourself). This also gives you some time to develop a persona and then get garb to match that persona - rather than buying some beautiful Elizabethan outfit from your local Laurel and then discovering that no, really you want to be Middle Eastern... or have an early Norse persona... or whatever. Basically, don't invest a lot of time or money into your first garb - first decide what it is your really want.
All of that said - what DO you wear to your first event? Suggestion the first: borrow! That's what loaner gear is for.
Suggestion the second: cobble something together out of your closet. Pants (not jeans!) with no obvious modern fastenings or pockets (cargo pants are right out) and in a believable medieval color (doesn't have to be 'boring' or neutral, but avoid anything that suggests you've dipped your clothing in nuclear waste) plus a loose, 'peasant style' shirt will work. Some patterned pants work well, too; plaid or striped pajama pants from your local Target would probably fit this bill.
Suggestion the third: make something! A basic 'T-Tunic' is pretty much a longer, slightly fuller T-shirt and is more than acceptable as beginner (or later!) garb. (See links below for some how-tos.) There are also plenty of commercial patterns out there for medieval and renaissance-style outfits (although beware: some are more accurate than others; if you want SCA opinions on commercial patterns, search the web - we can be an opinionated bunch sometimes!).
A note on shoes: getting accurate medieval shoes can be expensive, time consuming, or both. Many people spend their lives in the SCA without period footwear. It's okay to wear modern footwear. However, if you can avoid tennis shoes, you should. The white color makes them look particularly modern; clogs, loafers, sometimes even bedroom slippers are all a fair sight better (and still easy to get!).
Something to eat off of - only necessary if you choose to eat feast! Again, you can probably borrow period-esque feastgear. If not, however, a bowl, spoon, knife (something reasonably sharp - steak knives generally work well) and cup are all you need. Add a plate if you're feeling decadent. If you have something that doesn't look intrusively modern, so much the better.
Your First Event
So - you have garb. You have feastgear. You're all set for your first event. You get to site, check in at gate... and then what?
The most basic answer here is 'have fun.' The SCA is a hobby and we participate for entertainment. If you're not having a good time, something is wrong!
The more complicated answer... explore the event! Check everything out! See what's going on... there might be a tourney, where armored or rapier fighters challenge each other and complete glorious feats in pursuit of victory. There might be classes on everything from actual history to 'how to run the SCA' to different A&S activities. There might be performances of period music or the opportunity to learn some period dances. There will probably be court, which is one of the best places to witness the pageantry and splendor of the SCA.
Despite all this, you may want to bring something to do. It's nice to have something to occupy your hands while you watch fighting, chat with friends, or just chill out. Events are often a great time to get some work done on your SCA projects.
Wander around. Check everything out. Go up to people and say "Hi, I'm So-and-So. I'm new and this is my first event! Can you tell me more about what you're doing/what's going on here?" Chances are, they were just waiting to be asked!