The joy of kicking a football in the summer. My three year old loves football. He's not very good at it, but he enjoys kicking a ball around and well, isn't that part of the fun? Playing for the sake of it. No pressure, no competitiveness, just simple and silly fun. Why else are we alive, anyway, if not to enjoy it?
Jumpers for goalposts. Actually, as a goalpost this is perfect for your needs. However, it is not small (7 foot by 5 foot, so, too tall for Dad to stand in it, for example), and being steel, isn't light. It's sturdy as well, having been sat out in the garden for a few weeks in storms and rain without moving, a a good, low centre of gravity and a strong net though now starting to get some holes. As far as goalposts go, it is strong, sturdy, but heavy and bulky. Ideal for the garden, not for taking to the park.