Suggested by Tammy:
What items have you ever used as a bookmark? What is the most unusual item you’ve ever used or seen used?
So if you can read this and tell me what it is, I'd love to know! But whatever it is, it's definitely the most unusual thing I've found in a book!
UPDATE: After consulting with a colleague of mine in the Jewish library world (my boss, actually!) I've confirmed that the document is a ticket to a High Holy Days service held in Tel Aviv, in pre-state Israel. HaZafon is a neighborhood there and all of the other geographic markers check out. Thanks for everyone who wrote in with their ideas and translations!
As for what I use, mostly I just dog-ear. I know- I know. Bad!