A Stickman in a pine tree.
I first became aware of Stickman puzzles quite a while back. I saw this chess set that tickled my fancy. Then I saw the price it sold for at auction and decided it could keep on tickling me I would never be able to afford a Stickman. Looking back, I see they have gone for anywhere between $1100 and $1750. Over the years the price has remained pretty constant. Better than most puzzles which don't seem to hold their value until you get a crazy collector who just has to have it. Allard has blogged about it here.
I met Robert (aka Stickman) this past year at IPP. He is an amazing bloke! Very quiet, very humble, but oh so talented! Some of the puzzles he makes are truly astounding. Over a cigar I managed to sweet talk him into selling me a "Little Game Hunter" I really love this puzzle and am so glad I convinced him I had to have it.
I have managed to find a small list of some of his boxes at the bottom of this page. Over on the wiki there is a more filled out listing of his collection but there are still a few missing.
If you are simply interested in his work, there is a puzzle book that he's put together. You can get a copy of it over at cubic dissection. Eye candy to an extreme!