In most parts of the country, it is steamy, sweaty, dear-God-just-let-me-lie-here-until-it-passes hot. So I'd never ask you to do anything too strenuous. Just make a quick fresh whipped cream (hey, you get to open the fridge to get out the heavy cream and I won't mind if you stand there for a bit.)
Layer the cream in a pan with some chocolate wafer cookies. Cover the pan in plastic wrap and put it in the fridge (OK, go on, take another quick fridge dive). 4 hours later, during which you can by all means can be hugging your AC, spread the top of the cake with the last of the whipped cream. Then freeze it, slice it, and cool on down. That's classic ice box cake, and it's glorious.