Overheard at the booksale, from a kid sitting on a box of books: "Mommy, are we going to the library tomorrow?" (And he didn't say it in a "please no" way" but in a "we always do so we still are, right?" way.)
Spoils of Half Price Books a couple weeks ago and the library booksale. A pretty decent chunk is randomly grabbing things at the booksale that I can conceivably see myself reading at some distant point in time. This actually accounts for a lot of my backlog. It is quasi-separated by genre to save you from scrolling past too many books you have no clue about! Or something.