-Scrap Wood, lots of it (your local techshop should have a pile ready for the pickins')
-Screws/Nails/Whatever holds stuff together
-Varnish (if you want)
Step 1: Measure!
Mine was 15''
Step 2: Find What You Need!
Think about what you need to balance Form/Function
I went for some things to support and reinforce the structure
Step 3: Clamp/Start to Put It Together
(the wood I used for the legs were a pretty thin but I made it work ;)
Step 4: What Else Do You Want?
Step 5: Finish Up & Varnish!
Step 6: Put It in Your Room & Put $#!% on IT!