Never thought if this till you posed the question, but what about a no-purchase thing like have people each donate a book, then hide them. It would be like a bookswap with added element of surprise. Pretty much everyone has a book or two that they think it would be nice to pass along, but that they don't have a specific person in mind. Maybe the group you'd like to do this with even has a common interest -- say cooking or nature or gardening or self-help or ... could be just about anything! Or randomness!

I remember a number of years ago reading about something where people would leave a sharable book in a random public location just to do a little random act of kindness (and encourage reading ) I think they put some kind of note in there with the name of the project and encouraging the finder to participate. (At any rate, a note indicating it's intentionally gifted would be a good idea.)

This concept of donate-swap with the hide and seek game element could be used with so many different things! (Some might be best to protect with a plastic bag before hiding -- You'd just want to make sure to keep track, so nothing gets left behind environmentally speaking).

I'll now probably spend the afternoon obsessively thinking of all the things this could be done with, lol!