Exercise to do in summer?

[Cheadles]

Okay so im in australia and its going to start getting very hot (around 40 degrees celsius). The town pool is about 10 km away and it would be packed any way, so no room for me to do laps. I can't really do anything outside because i suffer from heat stroke. We do have aircons in almost every room to keep the house icy cold but i don't really have a lot of ideas of what exercises i could do inside... (i have the zumba dvd but i actually find that boring lol). Any other suggestions? thank you