Tomaz Kastrun checks what time it is:
Ever wanted to have a clock on the wall or in the office, that is not binary. But it is QR-Code clock. Well, now you can have it.
This useless R function generates new QR Code for every given period and tells the time.
Click through for the code. I could see this being useful in scenarios where you want to avoid people copying the QR code, so you embed the time in there. Then, your reader service can check to see if the time is within some valid boundary, returning an error if not.