If you feel you have too much spare time on your hands, you can always kill a couple of minutes by learning how to balance 17 dominoes on one upright domino.
it's also a standard trick in the discipline of cigar box manipulation. with cigar boxes the whole stack usually gets balanced on the chin. http://www.dube.com/cigarbox/stacking.php
I tried this with my domino set.. the solid ivory coloured type.. it all came crashing down on the first try...