1 foot = 0.16666 fathom = 0.3048 meter.
Of course, there are some things that you need to convert that don't have constant conversion rates, such as currency. If you want to convert US Dollars into Canadian Dollars (or Australian Dollars or any other type of dollar), what would be a fair conversion rate? Well, a great online tool for this kind of unit conversion is XE.com (which even allows you to look at historic currency conversion rates - limited to 20 years of data - and a whole bunch of handy currency conversion tools besides).
USD 1 = CAD 1.0050905404 on June 3, 2008
USD 1 = CAD 1.4530000000 on June 3, 1998
Of course, with the wonders of the internets, I find "SensibleUnits" - a place where you can convert standard units to "sensible" units.
1 foot = 6.0 AA batteries end-to-end = 30 stacked CD cases
UPDATE (2010-03-29): The "SensibleUnits" website is no longer functional. Kinda sad, since I was just wondering how many Great Walls of China long the Mississippi River is.