A rolling bridge: http://www.thomasheatherwick.com/projects_rolling_3.asp
(like literally. Kinda spiffy, although one wonders if it's possible to get trapped inside.)
And amusing portapotties.
http://www.youtube.com/watch?v=8gNsDp2N6yM
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And also this:
http://www.stumbleupon.com/mainpics/829603.jpg