lol err....lots of money?
You can buy temporary, even daily insurance (we offer it but min of 14days, max val £15k and not that higher grp cars) so your best bet is to type "daily insurance" "temporary insurance" "short term insurance" and a few variations along that theme into summat like Google and see what comes up.
You will probably find most short term insurers have quite strict rules on driver age, type of vehicle, value etc tho as the premiums they take are a lot lower than annual policies so they have to be very carefull who/what they insure as any large claims could wipe out the premium they have taken for the last few months etc