Dan's advice is pretty good. Go to learn. Try to relax and enjoy being around other referees. If the Yanks and Red Sox are playing during the camp, go down to TGIFriday's and watch the game with Dan. (I'm assuming that he'll be willing to meet you for the game, since he doesn't have any friends!
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The other thing I'd suggest is make sure you're prepared physically. Make sure you know if you should have pants or shorts. (The first time I went to Nunn-Better, I didn't do that and I had to run to Walmart to buy black polyester pants.) Have your rulebooks. Be in shape. Take an extra pair of shoes, in case one splits. If you eliminate all those little things that could distract you, you'll be able to concentrate on refereeing. Good luck.