What's the best thing you ever got at a used book sale?

As some of you may know, I'm a vice president at my synagogue. We have a yearly used book sale over the Martin Luther King Day weekend. Here's the announcement, cut-and-pasted from the shul's website:

Gently-used Books, Tapes and CD/Record Sale. Our fifth annual event will be held Sunday, Jan. 14 thru Monday, Jan. 15. Browse our fabulous collection of literary and audio treasures!

Beth El is at 3830 Seminary Rd., Alexandria, VA. 22304.

The book sale starts at 9:00 a.m. on Sunday the 14th and runs all day. The book collectors start lining up hours in advance. They are a quirky sub-culture and a people-watcher's delight.

The sale runs from 9:00 a.m. until mid-afternoon on Monday the 15th.

For those of you local to DC or Northern Virginia, it's worth checking out.

If you come by, we're likely to see one another. Ask anyone who seems to be in charge whether David the bearded Vice President is around. Even if I'm not, let the folks at the register know you're my guests. It won't get you a further discount, but, in most cases, it should get you a smile. (I think.) (I hope.)

Last year I found a complete paperback collection of Gary Trudeau's "Bull Tales" strips, the genesis of Doonesbury, from the Yale Daily News. For 50 cents.

There's a lot of crap to sift through, but also some real finds.

What's the best thing you ever picked up at a used book sale or in a used book shop? I'm expecting your answer to be a book or tape or video, but if it was a pair of horny Rumanian gymnasts, that's worth sharing too.