We would like to recommend to you an exhibition in Germany: Bernhard Deutsch is a German artist. He is making art-machines since 35 years. In Schwäbisch Hall you can see about 70 objects (insert a coin or press a button) from 12th of July to 15th of September 2013 (Hällisch-Fränkisches Museum). Finally all the objects are to sell - there is an auktion - happening. Have a look:
Here's the site with Google-garbled translation: http://www.nurzu.de/expo2013/
See also: http://www.nurzu.de/rundgang
Unfortunately, the postage-stamp-sized images really don't do justice to the objects. Mr Deutsch (or Mr German, as Google Translate would have it) is a German Tim Hunkin, but with his own unique style.
All items in the auction start at 99 Cents with the hammer coming down particularly hard on any that don't get a bid. These will be promptly smashed to pieces after the auction. I'm hoping slot machine auctioneers will be following this initiative. I can't think of a better way to ensure sellers set sensible reserves and bidders remain alert.