Publicis E-dologic figured out a way to embed user data in IDF bracelets, and thus allow people to "Like" real world objects, places and events spreading the word about it on their facebook accounts. The implemented these facebook-bracelets at the Coca Cola Village, a watersport, sunbathing, gameplaying amusement park activity-thing for teenagers. When the guests arrive, they are given a bracelet ID which transmits an RFID signal, which they program with their facebook login. They can then "like" activities and places in the real village, and their actions show up on facebook. Teenagers are driven by vanity like everyone else, so there was a photographer present as well, if you wanted to tag yourself in any given image all you had to do was wave your ID bracelet to the photographer.
See the case study here:
CEO of Edologic, Enon Landenberg, says, "We are continuously looking for ways to connect the physical world with the virtual world. The idea behind "The Like machine" is an ultimate solution. It is an innovative and pioneering method, and through it the possibility to involve your Facebook friends in events and experiences that are happening to you around the world becomes a very true reality."
Pretty darn awesome.