Keeping cut tomatoes
Nothing really keeps them at their peak, but thanks to other Chowhounds, I've been able to extend for a little while by wrapping in plastic wrap and keeping cut side down on the counter. Someone else also suggested keeping cut side down on a plate with a bit of oil to protect the cut surface.
Try to avoid the fridge!
Also I've found some smaller heirloom tomatoes at the store that I can manage to eat in 1 sitting.