Building a humidor can be a challenging project. If you are competent or skilled working with wood, Popular Mechanics has published a great article on the web that shows you how to build your own humidor.
For the rest of us mortals, we will have to make do with purchasing a humidor. It is easy, convenient and cheap. Yes, you heard right. Cheap. We have a great selection of fine humidors at very low prices.
But there are other options. You can build a cheap cigar humidor using a cooler or a Tupperware container. If you find a fine cigar box that closes tight you can buy a humidor kit (hygrometer and humidifier) and stick it to your box with non-odorous glue or double face tape.
You can also build a large cigar humidor out of an old refrigerator or other large piece of furniture, but this is tricky, so be careful and follow the tips on the Cigar Smoker's FAQ.