Ukulele festivals, no matter where they are, are typically a great way to immerse yourself in everything four string for a day, weekend or week. I've been lucky enough to attend more than 25 festivals in the past five years or so; I enjoy writing them up to share what the experience is like to encourage other players to attend a festival, whether close enough to drive or so far away you have to fly. I've been to the Reno event three times and will be there this year, too. Here's a writeup of the 2010 Reno event (last year was a great time, too, but I took the photos and didn't get it written up and posted):
http://ukuleletonya.com/blog/2010/04/tahoe-area-uke-fest-march-19-20-2010. I also have accounts/photos of many other festivals elsewhere at my site; my goal is to get every ukulele player to take the time/effort to attend a festival.
At a festival you'll find lots of opportunities for learning, buying, jamming with others and hearing some great performers. Bring a notebook/paper/pen for class notes; a lightweight music stand can be helpful but sometimes it's just easier to prop your workshop class handouts on your lap than haul one around. If there's a workshop you *really* want to attend, arrive early and definitely sit up front (learning materials brought by the workshop instructors sometimes run out and sitting up front gives you a better chance of getting one). Some workshops are all lecture but most are a mixture of the instructor talking/demonstrating and then giving you a chance to try out what you've learned. Most instructors are okay with you audio/video recording the workshop but *always* ask first.
Buy tickets to the concert. Make friends with people you're sitting next to. Be open to opportunities to jam/kani ka pila with others after the concert or during breaks in the day. Connecting with other players is really the joy of attending an ukulele event.
Bring a credit card/cash for the vendor area. Many will even take checks. Wander through the vendor area early and often. If you see an instrument (or other item--music book, accessory, jewelry, whatever) that really thrills you, buy it sooner rather than later. Most vendors only bring limited stock and it'd be a shame to return six hours later, after your last workshop, and find that item you'd drooled over already sold. I know this from experience. Talk with vendors, try out ukuleles of all kinds.
When "testing" an ukulele, be polite: make sure you're not wearing anything that would inadvertently scratch the instrument (belt buckle, buttons, etc.) and your fingers aren't sticky/gummy from anything. But don't be afraid to try instruments that you think are "above" your price range or playing ability. A festival is a great opportunity to get a feel for a wide variety of instruments that most of us don't have nearby to try. My first festival (back in Rhode Island!), I wandered through the vendor area twice with my hands politely behind my back; I was a new player (as in three chords, barely) and I didn't feel I really "deserved" to be able to play those nicer instruments. Finally a vendor smiled at me: "You know, you're allowed to play them," he laughed. So I did--and I ended up with a custom instrument I never would have considered otherwise. Before then, I had no idea that a nice instrument could feel and sound so much nicer to play!
If things are noisy at the vendor area, ask to take the instrument over to a wall/corner and play facing that surface. The sound will come back to you more easily there. Also have someone *else* play the instrument for you as you face them; you may be able to hear the sound better that way.
Get plenty of sleep ahead of time--you'll need it!