This table uses an old road sign for the top, but you could use a lot of things for the surface -- laminated wood, plywood, an old piece of countertop, butcher block, or whatever else you can scavenge that's about 30" square. The advantage of the road sign is its relative light weight and high strength, making this table truly transient. All the wood was scavenged pine, cut-offs from tongue-and-groove flooring, along with two pieces of cedar.
I built it in about a day. It cost somewhere around thirty dollars to make, as I had to buy hinges, bolts, nuts, some copper fittings, and super-strong neodymium magnets to hold the legs in the folded position.
It is currently for sale at the Grace Aberdean Gallery in Tuscaloosa, AL: http://graceaberdean.wordpress.com/
Thanks to Ramell Ross for the first five pictures. http://www.ramellross.com
You will need these materials:
Approx. 20 running feet of wood ripped down to 3/4" or 1" square
Approx. 6 running feet of wood ripped down to 1-1/2" x 2"
Suitable table-top material 30"-36" square (old sign, laminated wood, 3/4" plywood, etc.)
4 small triangle strap hinges
16 3/8" dia. neodymium magnets
8 1/4" x 2-1/2" machine bolts
24 1/4" cut washers
8 1/4" nuts
a handful of pan-head screws
You will need these tools:
Impact driver (optional)
Step 1: X-Bracing
Once you have two equal pieces cut, mark the center on one and cut the width of its matching piece out of it, so you have three pieces to compose your "X". Drill a 1/4" hole about four inches from the center of the "X" on each piece, making four holes to hinge the legs to. Sand liberally, seal if desired. Attach the legs to the underside of your table top with superglue or clamps to hold them in place temporarily, then pre-drill and screw them in from above. If your table top is not metal, and sufficiently thick to take screw from the underside, you can screw in from below to keep the surface smooth.