Try drawing; it's a nice quiet activity to keep you cool. There are lots of drawing books available for you to checkout. Consider these:
Sketching Outdoors in Summer by Jim Arnosky
DragonArt by J. Neondragon Peffer
Draw 50 Monsters, Creeps, Superheroes, Demons, Dragons, Nerds, Dirts, Ghouls, Giants, Vampires, Zombies, and other Curiosities by Lee J. Ames
How to Draw Lettering by Judy Tatchell
Adventures in Cartooning by James Sturm
Drawing Words, Writing Pictures by Jessica Abel
And there's more!