I wonder what the socialist equivalent of a charity bake sale would be? Would you get a bunch of kids into the kitchen and say, "Okay, guys, we're going to make some cookies, and each of you can make as many or as few as you'd like, but we're going to share all of them--no dibs--and it's up to you whether we make enough for everybody?" Even outside the political allegory, it'd be an interesting (and somewhat cruel) social experiment.
If the kids fail to make enough cookies for everyone, due to short-sighted planning or a few kids failing to pull their weight, you will create a tiny microcosm of an actual planned economy. Fingers will be pointed! Grudges will be had! Kids will blame each other for not producing enough cookies, for consuming too many, for exercising power disproportionate to the benefits of their leadership; arguments will break out over whether or not some children should be forced to give up more than others for the sake of the common good. Perhaps a few children, in an heartbreaking and unintentional allegory of the hardships of their ancestors, will share or sacrifice their own cookies so that there will be enough for everyone else. Many tiny hearts will be broken! Even when you bring out the tray of backup cookies you secretly prepared in advance (yay government bailout) so that no one will be left miserable and crying, the sting of social responsibility will last them a lifetime. A cookie just isn't the same when you haven't lovingly molded the dough in your own hands.
If the kids succeed in making enough cookies for everyone to share, they will learn nothing except that cookies are delicious. But your faith in humanity will be restored.