I have seen that quite a few people have got things like stamps and business cards to leave when Geocaching and I couldn’t resist joining the craze. Just bought a self-inking stamp from Self Inking Stamps (NZ). The stamp contains a QR code to this web site and the founding element of computers - a NPN transistor – now superseded by better technology, but a good reminder of where it all comes from.

The stamp itself is very good - laser cut and very accurate. It does require a bit of pressure to get the QR to a quality that can be scanned by a cellphone though. The first GC I used it on was GC206R0 - A Secret Harbour View