Long distance targets - Gallon plastic milk cartons with a bit of food coloring and a gallon of water
Leave the cap off.
Haven't tried this one yet - read about it on the net somewhere (here??)
Take a brightly colored piece of cardboard (or paint a piece of cardboard) - Put stretch plastic wrap over it (tight). Paint the plastic wrap a color that contrasts with your cardboard. When it dries you have one of those targets that show where you hit.
Let me know if it works