I had friend that used the 'Amazing Graze' - you can put carrot pieces, pelleted grain, hay stretcher pellets, timothy cubes etc in it. I've had luck washing out an old bleach bottle, cutting a small hole in the side, and hanging it in the center of the stall. I'd put Blue Seal Hay Stretcher pellets in it, but you could but anything you like in it. It gets bashed around a lot, but then you just replace it with a new bottle.
I use empty gallon jugs- water, milk, supplement, vinegar.. anything. Even when they are smashed up- they are still entertaining hanging on a stall wall until you can get a replacement. Most of mine get smashed almost flat in one night but bring weeks of enjoyment!
I also use old jugs, mainly the empty corn oil jugs. I'll stick a few stones in them so they make cool noises when they shake them. My yearlings LOVE them, especially to get the "I want food" idea across to me. They also like to have jug shaking wars.