Tuple unpacking works.
(element,) = myset
(By the way, python-dev has explored but rejected the addition of myset.get() to return an arbitrary element from a set. Discussion here, Guido van Rossum answers 1 and 2.)
My personal favorite for getting an arbitrary element is (when you have an unknown number, but also works if you have just one):
element = next(iter(myset)) ยน
1: in Python 2.5 and before, you have to use iter(myset).next()