I think it's totally unpredictable. To be safe, try getting there as early as possible. Maybe more people show up on a Tuesday/Wednesday, because everyone seems to think "hey, it's gotta be less busy than a Friday/Saturday!" I went on a Saturday, got in line at 10 to 10 and had my choice of the matinee or the evening show (ended up on the left side, the first two spots for the eve. show). Some people have said they had to get there at 6/7 am, and then Yankeefan got there at 9 w/o any problems getting a spot.
But when did New Hampshire become--Such a backward wasteland of seatbelt hating crazies?...I mean, only 40 people actually live there. The others are just visitors who come for the tax-free liquor and three inches of novelty coastline. John Hodgeman on The Daily Show (1-30-07)