Oooh, me, me!!! I want to see your business card!
That's a really cute idea...instead of constantly whipping out pen and paper to write down your name & number, just give them your personal card. (Didn't we used to have those back in the olden days? I think they were actually called "calling cards." Will someone more etiquette-savvy chime in and let me know if I'm recalling correctly?)
Anyway, have fun with the cards!