I almost did a Tim and buried a recessed hook in my floor but decided a mobile weight would serve me better.
You need 2 bags of quick set concrete, length of chain, and a small tie down hook with a ratching winch fitting ($3 at Home Depot)
Using a plastic box as a form does 2 things 1) it holds just enough 'crete to pull the nose wheel off the ground, 2) it makes it easy to slide the contraption into a corner when not in use.
I buried some chicken wire in the 'crete so it wouldn't break up. Stuck a few spikes thru the buried chain for reinforcement