One of the best practical jokes I'd ever heard (and wish I'd seen) involved careful manipulation of fortune cookies to include fortunes that were very personal to the recipients. My cousin threw a party, and served Chinese food ordered from a local restaurant. He also obtained some fortune cookies, delicately removed their fortunes, and inserted some of his own. (Yes, he probably did it the hard way.)
After the meal, when each attendee opened his fortune cookie, s/he found a fortune that looked real, but hit very close to home. Some of the cookies included ribald suggestions, double-entendres and inside jokes that no one except the attendees would understand.
The first reaction was utter astonishment at how a fortune cookie could know so much about one's personal life! As people compared fortunes, they all realized that it was a con and they had a good laugh.
