kw: observations, monuments, folk art
I stumbled upon an account of Carhenge, tried a search on "*henge", and found quite a collection of things people have "henged" since Stonehenge became famous (again) with the publication of Stonehenge Decoded a generation ago. Eventually I came across the Clonehenge web site, dedicated to "The 47 Large Permanent Replicas". A few of the images below are from that site; the others from sundry spots, mainly in the blogosphere and photoblogs. There are many more.
Carhenge was one of the first large installations, and has inspired other henges of castoff large, boxy things, such as refrigerators and toilet stalls and empty cable spools:
Large installations like these tend to be permanent, though I imagine a half dozen cars full of enterprising collegians could descend on almost any town dump and produce a Fridgehenge or Washer/Dryerhenge in a pretty short time. They'd probably be required to dismantle it pronto, if they didn't vamoose!
More ephemeral henges can be produced from whatever is available, such as split wood or beach stones:
I imagine little circles like these are fun and quick to build, and much less threatening to property values.
I've spent many an hour collecting beach stones for various reasons, such as piling up into walls, decorating sand castles, or painting as "pet rocks." I'll have to try a henge out at the next rocky coast I visit.
The most ephemeral of all are built with food (here, cheese, Twinkies, and potatoes). These no doubt vanished soon after being completed: