Guinness' QR code glass is actually a good blend of beer and technology: The QR code is printed on the glass and only works when Guinness (or another black/dark liquid) fills the glass, so don't try filling these glasses with lager, etc. Once full scanning the QR code launches a site that easily/automatically tweets, checks in, posts a status update or sends an Instagram photo about where you are and the fact that you're enjoying a pint of Guinness.
For those of you who don't remember, last year Heineken (actually, I think it was some college kids) conceptualized a bottle opener that would automatically invite Facebook friends to your house for a party every time you opened a bottle. Seemed exhausting to have a party every time you wanted a beer. See the video here: http://www.newsy.com/videos/new-heineken-bottle-opener-goes-social
Guiness QR Code: thumbs-up | Heineken's (almost) Social Opener: thumbs-down
If you want to see some other cool uses of QR codes go to http://fivecoolthings.blogspot.com/2012/05/three-nice-uses-of-qr-codes-emart.html
Via Tina Stock