Two Lego robots are making their rounds on the hyper links. I’ll just repeat them here:

A Lego felt tip printer, including CUSP / OS X printer driver
http://www.b3ta.com/links/Lego_printer
http://www.pcpro.co.uk/blogs/2010/06/02/the_genius_of_the_lego_printer/
http://hardware.slashdot.org/story/10/06/02/1819230/The-Genius-of-the-Lego-Printer

And a Lego Maker Bot, or MakerLegoBot
http://www.battlebricks.com/makerlegobot/
http://www.wired.com/gadgetlab/2010/10/legobot/?pid=652
http://hardware.slashdot.org/story/10/10/20/1348206/A-3D-Lego-Fabricator-Made-of-Lego