  Foster and Hart proposed an operational measure of riskiness for discrete
random variables. We show that their defining equation has no solution for many
common continuous distributions including many uniform distributions, e.g. We
show how to extend consistently the definition of riskiness to continuous
random variables. For many continuous random variables, the risk measure is
equal to the worst--case risk measure, i.e. the maximal possible loss incurred
by that gamble. We also extend the Foster--Hart risk measure to dynamic
environments for general distributions and probability spaces, and we show that
the extended measure avoids bankruptcy in infinitely repeated gambles.
