If you know Latin, this might not be news to you, but if not, you might find this amusing.
I heard about Alibris.com quite a while before I started using it. A lady at the church I used to go to regularly bought books from them and recommended that I check out their site. I started pondering the name and then I realized that the person who named the site had played one of my favorite games: making a bilingual pun!
"Alibris" is actually two words in Latin: a "by" (as in the agent of a passive verb) and libris "books" (ablative case, which among other things is used to indicate the agent of a passive verb). Thus we have a phrase meaning "by books," as in, "He was hit by books that fell off the shelf during the earthquake." But of course, this sounds the same as the imperative clause "Buy books!" which is what Alibris wants you to do.
Ah, those clever Romans!