Ideas for an Easter egg kinda gift?

[cn-i-crash-here.livejournal.com]

I haven't lived in metro Camberville in a while, but I still make periodic visits. My next visit will be in a couple weeks.

Now I've found out that a friend of mine from here in Oregon is visiting Boston too. But I'll miss him by a few days. Since I won't see him, it would be neat if I could plant a present for him there and email him in October with some oblique clues to finding it. Ideally, it would be something novel, cheap, and unlikely to be snatched before my friend finds it.

So far, all that has come to mind is a coffee shop ten-punch card. I would get nine punches on it and leave it in the store's card container for him to retrieve and enjoy. That idea isn't too exciting to me; but anyway, I don't know of a shop that does those punch cards, never mind one that holds them for customers.

Ideas? My friend is male, early 20's, and a serious musician (trombone). He has an outsider's love of the Boston area, so he might appreciate some local color, too.