But you know what is the best day for a library book sale? It's the last day, the $5 per box or $2 per bag all-you-can-carry day. It's so awesome!
This year I went twice - on the opening day (stood in line for over an hour) and on the closing day (stood in line for about 20 mins). And it was a blast. On the last day, hubby and I filled a giant box full of books (including a brand-new non-library copy of the Da Vinci Code), paid our $5, and got out with enough reading material for the entire 2010 (plus some gifts).
That evening I couldn't wait for Mr. M to go to bed since I wanted to build a tower of all the books we bought. Call me a dork, I dare you.