Humongous Sunflower
If you're wanting sunflower seeds to eat, this is your plant. The seeds are larger than the seeds of the standard variety, Mammoth. And they come from immense flowers up to 3' across. As the seeds mature, the stalks bend over, both from the weight of the developing seeds and to protect them from rain and birds. (Birds will still seek them out, though, so be vigilant.) You may want to plant them in triangles, about 2' on a side, so you can tie them together for mutual support. One fun project I've seen is to plant them in a circle about 8" across, to make a kid's summer playhouse. (Growing beans or morning glories up the stalks adds to the fun.) But when it comes down to it, anybody of any age can enjoy these and they are a serious source of high-quality food.