When we play D&D (and other pen and paper roll playing games) we usually use a pad of grid paper and miniatures. The pads are big enough that they don't leave much space on the long edges of the tables meaning that every time we need to change to a new sheet everyone inevitably needs to lift their character sheets, dice, food, drinks etc. before the sheet can be changed.

So I decided to make a tabletop to lift the pad off of the table to allow the players to put most of their items below the playing surface instead.

The other bonus is that this tabletop has hooks so that the pad can be stored in a hanging state instead of rolling or folding it, which means you can keep the pad flat so your minis don't slide all over the place.

This build is super simple and shouldn't cost more than about $20 depending on what you already have on hand.

Step 1: Materials

You'll need:

24" x 48" x 11mm sheet of G1S (the nicest surface finish I could find) plywood. Avoid sheets that have large bends. You could also use MDF, just make sure the it's thick enough to support weight without bending in the center, or add an extra support in the center.
About a foot of 2x4, or some fancier furniture legs if you wish.
8 wood screws.
2 screw in hooks

Tools:

Saw (circular, table, and/or miter saws would be helpful but not required)
Sandpaper
Drill
Countersink bit
Router (optional)

Step 2: Cut the Plywood

Grab that sheet of paper and measure where you want it to sit, and how long you want the table to be. Since the paper and the plywood are both 24" wide you only need to trim down the length.

I made my table about 43 inches long, and positioned the hooks about 6 1/2 inches from the edge (don't put the hooks in just yet). This extra space is useful for the DM to set models or other things.

If you have a longer table you could just skip this step, but I felt it was nice to cut it a little shorter to make sure the people at the heads of the table (especially the DM) have a little extra room.

Step 3: Cut the Legs

Cut the 2x4 to make the legs.

If you use the natural width of the 2x4, like I did, it doesn't matter much how long you make the cuts, but leave enough room to get 2 screws in. This will raise your table by 3.5", because 2x4s are stupidly named.

If you want your table to be taller, just make longer legs, but make sure they're all the same length.

Step 4: Round the Edges

Round off all of the edges of both the plywood and the legs now with sandpaper or a router or whatever you have available.

This is also a good time to give everything a good sanding.

Step 5: Mark, Drill, and Countersink Screw Holes

I placed the legs of my table approximately 6" from the edges of the table, and the one set is directly under where the hooks sit.

So figure out where you want to place the legs, mark and drill pilot holes, then countersink them so the paper can lay flat.

Make sure you drill pilot holes in the legs as well. You don't want them to split.

Step 6: Attach the Legs and Hooks

Screw in the legs and the hooks. Make sure you orient all of the legs so they are the same height.

Step 7: (Optional) Finishing and Power

The table is now completely usable. But you may want something a little fancier.

I've been using mine with just the bare wood, but some of the things I've been considering are:

Staining and varnishing
Painting a flat color
Painting a mural (covered with a clear varnish)
Applying whiteboard or chalkboard paint, and making permanent grid lines, so the paper is no longer needed
Cutting shallow grid lines directly into the tabletop (but I don't have a table saw and wouldn't even attempt it with a circular saw.

I'm also thinking about adding power to the table. The easiest option is probably to buy a powerbar that also has usb outlets and mount it to the underside of the table.