I have to interject here... My son was born last February (2008) and I brought him to Pennsic. It's actually the perfect time to go, since at 5 months they are strong enough to sit up (mostly), but don't go anywhere when you put them down. Bring lots of food, blankets and patience, and it's pretty easy.

Now this year, when I'll be bringing a one and a half year old - who is already into everything - that I'm worried about. :)