I love stuff like that:
Semapedia “combine[s] the physical annotation technology of http://semacode.org with the availability of high quality information using the free online encyclopedia Wikipedia.org” and thus “provide[s] free relevant ad-hoc high quality information to mobile users in the real world.”
a semacode is an optical barcode that contains a URL internet address, e.g.:
With Semapedia technology you can connect physical entities with their wikipedish representation via attaching semipedia printouts to those physical entities – a reentry of the symbolic into the real. Details of how to do it and the soft- and hardware requirements are given here.