18" x 12" 1/4" thick Acrylic sheet - we got one twice that size and cut it down. The 1/4" thickness makes the channel easy since the LED strips are also 1/4" wide, but you could do this differently and use thinner plastic.
18" of 1x4 pine
36" of 1x2 pine
18" of an LED strip - available at many online stores - we used http://www.hobbypartz.com
a 9v battery clip
1 5/8" drywall screws (6 of them)
Step 1: Wood Frame
Then we put the acrylic in place to make the gap the right width, and clamped the second 1x2 to the first with the plastic in place. As before, we used three screws from the bottom.
Now, the plastic slides into the groove we created. The LED strips are also conveniently 1/4" wide.
Step 2: Acrylic Diagram
We etched the plastic by hand with a Dremel tool with a small stone grinding tip. The metal spiral tips tended to get out of control. Do some practice on scraps first to get the hang of it. We drew the diagram with washable markers, then went over the lines with the Dremel tool. Be sure to leave extra room at the bottom for the frame.
I noticed afterwards that scotch tape on the back lights up too - you may be able to do all of this with tape or glue or something - that could be even easier.
Step 3: LED Lighting
That's it! We have extra plastic - maybe make a light up grave stone next!
LEDs, the bacon for Makers! :-)