Perhaps a bit late, but...how about this?
Find a scene in a park on a nice day with some things you can place in the foreground and background. They can be any type of items...water fountains, shrubs, kids playing, signs, benches...just so they are various items at different distances from the camera. The closest subject might be four or five feet away while subsequent objects are at increasing distances as far away as the other side of the park. Pick an item in the middle of the group (halfway across the park?) and focus on it using the fastest shutter speed feasible and see how many items you can get into focus along with it. Take a picture! Decrease the shutter speed a notch and adjust the aperture accordingly to get the same exposure as the first picture. See how many of the items you can get into focus with this setup and...take another picture! Keep decreasing the shutter speed and adjusting the aperture to accommodate the shot. The slower the shutter speed, the more items you should be able to get into focus (increased depth of field) and see how far you can go and still get clear, crisp handheld pictures without using a tripod. This is good practice for taking low light pictures with slower shutter speeds. Brace your camera against your body or brace yourself by kneeling, leaning or even shooting prone for the slower shutter speeds.
Remember to compare your photos when you get home and check that varying depth of field to see how it affects the composure of your shots.
Anyone else got any fun stuff to try?