I have wanted a drafting/drawing table for awhile, but did not want to spend a few hundred dollars on a large commercial one.
I created this design to fit onto a 90 x 180 cm piece of plywood (standard size here in Japan), and it can be scaled to 4 x 8' using the included Google Sketchup 3D design file.
(Click on the [i] at the top left of photos to see an enlarged version.)

Materials used
- One 90 x 180 cm piece of plywood (1.2 cm thick)
- One 60 x 90 cm laminated wood table top (1.8 cm thick)
- One 2.7 x 90 cm strip of wood for the table top lip (0.5 cm thick)
- Two 4 cm dowels (1 cm diameter)
- Two 2 x 5 cm supports for arches (2 cm thick)
- Several 3 cm wood screws to hold the table base together
- Two hinges for the table top
- Four 1.2 cm screws to attach hinges
- Wood putty to hide screws
- White paint (optional)

Tools used
- Handheld circular saw
- Handheld jig saw
- Power drill
- Phillips screwdriver ("+" tip)
- Countersink drill bit
- Straight-edge guide and clamps for straight cuts

The attached Sketchup file shows the 3D assembled drafting table, as well as the cutting pattern of the plywood.
I have entered this instructable in the Shopbot challenge, I appreciate your vote - thanks!

drafting-table-plywood2.skp
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Step 1: Cutting the Plywood

The first step is to cut the plywood sheet (measurements included in the diagram, or refer to the Sketchup file).
I used a circular saw for the straight cuts, and a jig saw for the arched supports.
The square cutouts in the top of the base were made by drilling holes and cutting out the square with the jig saw.
I used plywood that has one side pre-painted (used in construction for concrete forms) which provides a smoother surface for painting. I painted the outside surfaces white to match my computer desk.

Step 2: Assembling the Drafting Table

Putting together the table is pretty straightforward.
I do not have a biscuit cutter or dowel jig etc. so I just attached all the pieces with wood screws.
Screw locations are not shown in the diagrams, but it should be fairly evident where to insert them.
(The back side supports are screwed from the left and right sides. The top piece of plywood is screwed from above.)
For the arched table top supports, I inserted screws from the underside so the table top is smooth.

I used a countersink drill bit so the screws will go 1 or 2 mm below the surface, then applied wood putty after inserting the screws.
This way the screws are not visible after painting.

Step 3: Attaching the Hinged Table Top

I chose to give my drafting table top an overhang of 2 - 3 cm on each side.
This makes it a bit more difficult to attach the hinges than if the table top is flush with the top of the base.
I attached the hinges to the top of the base first, then to the underside of the table top (this requires an assistant).

In the second photo you can see the type of hinges used. The type I used fit in between the table top and base and take up less than 2 mm thickness, with the pin part of the hinge hanging over the edge of the base.

The arched supports take a bit of work to get lined up with the square holes in the top of the base.
I inserted screws from the underside, and outside as you can see in the photo.

After mounting the arched supports, I drilled 1 cm diameter holes from the left and right sides.
I supported the table top at the desired angles, then drilled from the outside all the way through each support in the appropriate position.
The 1 cm dowels fit through both holes to support the table top at the desired angle.

The last step was to attach the thin strip of wood along the bottom edge of the table top (to prevent things from sliding off the top when at an angle).

Step 4: The Finished Drafting Table

It's not the slickest looking drafting table, but it cost less than $50 (USD) to build, and it more than does the job.
I use mine mostly for working on hand carved and/or painted signs. (The black material is a non-slip rubber mat that is great for keeping wood in place when carving or sanding etc.)
I would recommend using plywood that is 2 cm (3/4") if available, for greater strength.