I got to thinking on the way to work how to calculate a square root without the aid of a calculator. At one point I was getting into algebra (I got from x=a*a to x/a=a and got confused and so gave up). When I got home I remembered decided to check it out. It turns out the answer is... guess. The ever helpful Dr Math (http://mathforum.org/library/drmath/view/52609.html) has some answers but essentially that's it.

Now perhaps a better question is why was I trying to calculate a square root while walking along sipping my morning coffee? Maybe later :)