Interesting idea, QR Code Twitter Bingo!
A link available at the site will create random bingo boards that will tweet out a question when scanned with a QR code reader. Have your students then append something to the tweet.
It was used by the author by having participants at a conference submit a one sentence fact about themselves. As an ice breaker they went around and tried to find who the person was who fit that fact. Scanning the QR code once you find the person will auto generate a tweet with that fact. The participant would then append the twitter handle of who matches that fact to the end of the fact, thus allowing others in the room to get to know everyone.
Source: Teacher tech