Keeping In Touch

When I am out and about on my trike in the summer months, I meet a lot of people and some of these people I would like to keep in touch with.  They are people I would like to exchange emails with and one day meet again.  In these kinds of situations, I either do nothing, or I dig around for some paper scrap in my purse and a pen with which to quickly scribble down my information.  I have often thought it would be a good idea to have some business cards with me, maybe some translucent plastic business cards would be nice... or maybe I should call them by some other name since I don't have a business, lol.