For my 4-H Project, I'm building an incubator. It is called the "Sunny-Side-Up Incubator. It holds one standard chicken egg, and maybe 2 small bantam eggs. It is painted yellow (Sunny colored!) and did not cost much to make.
Supplie's:
Plexiglass
1/4" thick plywood
Yellow paint
Sharpie pen

Night Light
Hardware
Aluminum foil
Sponge

Tools:
Saw
Paint brush

Drill
Wire Cutter
Hot Glue Gun
First, I cut 2 3 1/2" by 3 1/2" plywood. Then, I cut 2 3 1/2" by 1 1/2" plywood and 2 3" by 1 1/2" pieces. Drill a hole into one of the larger pieces big enough to fit the bulb into it. I also cut 4 3 1/2 inch tall posts. Then I painted them with the yellow paint that I bought at my local Wal-Mart. Here's a picture:

45995_sunny_side_up_incubator_001.jpg

Second, I cut 4 pieces of plexiglass, but I'm not sure how big they were because at the end, we had to redo them a little bit, but they need to be 2 1/2" high. I also bought a night light, NOT LED :), and took off the shade. Then, I put non-skid things on the bottom of the incubator to help stop it from moving around on the table. Here's a picture:
45995_sunny_side_up_incubator_002.jpg

Then, I took the bottom piece and glued the 4 posts on to it about a quarter inch from every side like this:

45995_sunny_side_up_incubator_003.jpg

After that, I took the 4 smaller wooden pieces and glued them onto every post like this:
45995_sunny_side_up_incubator_007.jpg

Next, take the aluminum foil and cut it to size so then it fits on the bottom of the incubator like this:
45995_sunny_side_up_incubator_008.jpg

Then, take the night light and put the bulb through the hole that you predrilled. Then glue the rest of the night light onto the incubator like this:
45995_sunny_side_up_incubator_009.jpg

Next, glue the 4 pieces of plexiglass above the other pieces of wood with the hot glue gun. Then cut the hardware cloth and put it in the incubator above the night light for the egg to sit on just like this:
45995_sunny_side_up_incubator_010.jpg

Then, you're almost done, put the top on and write Sunny Side Up Incubator on the front. Then, drill holes for airflow. I haven't done this yet because I haven't gotten my thermometer yet. Also, put a small sponge in the incubator to add humidity. Here's a picture of what should be the finished product:
45995_sunny_side_up_incubator_011.jpg

One thing I would change is the size. I would make it big enough to fit 6 eggs........