One of the highlights of my Shetland trip was visiting the Unst Bus shelter.
There was even half a bottle of scotch in it for the weary traveller which of course I helped myself to.
en.wikipedia.org
The highlight of Orkney was being chased around the standing stones by a woman in a Werewolf mask. Oh and seeing a band Called "The Tribe" in Kirkwall. That was a night to remember. The Scarabray Neolithic village on Orkney is worth seeing but not as exciting as the other two highlights. Also there are cheap as chips internal flights to the other islands which are great fun and a good way to see the islands from the Air (Orkney not sure about Shetland)