Here's my one-hour trailer. I wanted a little beater flatbed to haul water containers with. I had the set of wheels and axle kicking around in the garage, salvaged from a kiddy trailer that someone had thrown away. I used the hitch arm from my Burley Nomad. I just put the rest together from scraps that were laying around. The bed is a piece of 3/4" plywood.There's a couple of lengths of square metal tubing underneath to stiffen the whole thing up. To attach the hitch arm I used pieces of plastic sink drain tubing and clamped them on under 1" pipe clamps, the arm just slides in and I used a 3/8 bolt to hold it in place. Took about an hour to build and works like a charm. I can remove the two by twos in a second and use it as a flatbed to haul anything. I used it the other day to haul two containers of water, seven gallons each. That's about 120 pounds of water and the wheels/tires/bearings seemed to be fine with the load. So, It's an ugly little thing, but it was free and it's perfectly functional.
UPDATE:
Found out today that it works great for getting groceries!