Since meetup.com is not incredibly well known in Zurich, I've decided to do some recruiting the old-fashioned way by posting a few flyers around town in some promising locations:
Google, if I can
I've attached my flyer so that anyone else can easily build off of a template. It's in .doc format, and the margins should be not more than .75in = 1.90cm.
I used http://qrcode.kaywa.com/ for making the QR codes.
Of course feel free to modify as you see fit, and upload your version if you like.