This is a very basic magic concept. Once learned, it can be adapted for close-up, classroom or stage magic using any available materials or objects.
You will need two tubes, one of which will fit inside the other, and an "S' shaped wire hook . The tubes can be two aluminum cans that vegetables or fruit juice come in or you can make them yourself from aluminum flashing. You will need to supply your own "load" to produce out of the "empty" tubes. This can be a beanbag rabbit, a silk scarf, a tissue paper packet for a Paper Hat Tear (See Fun-da-mental Magic Series #3), someone's watch or anything that will fit inside the smaller of the two canisters and hang on the hook.
Show the two canisters to the audience so that they cannot see into them. As you place the larger one on your magic table turn it over so that they can see that there is nothing inside it. Don't mention it. Just casually show it. Say, "One of these tubes is larger than the other." Slide the smaller loaded tube down inside the larger one, making sure that the hook catches on the rim of the larger canister. You can cover it with your fingers so it won't show. Say, "The outer tube is larger so I guess we can assume that means the inner tube is smaller." Lift the outer tube and the hook with its load. Pick up the smaller tube, which is now empty, from the table, flip it over letting the audience see that it is empty. Place the smaller tube back on the table and slide the loaded larger tube down over it. Make sure that the load doesn't get pushed up as you ease it back into the smaller inside tube. You now have a nest of appearently "empty" tubes with a hidden load in it. Make your MAGIC MOVES or say your MAGIC WORD and mysteriously produce the load.
You will need to be aware of the angle that the audience sees from. If they are seated below you or standing above you they can see into the open ends of the canisters. Make sure that you hold the tubes, especially the loaded one, so that no one can see inside. That would reveal the secret and spoil the magic.
This magic concept can be enlarged for stage use. You can use two bottomless trash cans or make concentric wooden boxes that will take a larger load such as a cage with a live rabbit inside. Make sure that the hook you use is strong enough to hold the weight of the load. Practice your moves and watch your angles.