What to see at a sheepdog trial?

I'm going to my first sheepdog trial (Fiber Festival in VA) and I'd love to
hear something of what to expect, what not to miss, that sort of thing. I'm
not competing, just spectating, but I'm keeping my options open for the
years ahead.

I've been to conformation shows and agility trials, but herding is all new!
Any words of wisdom from people who've been there?

--
Jess K. and mastiff pup Bree