The twin-size daybed, created by DIY maven Ana White and featured at HGTV, really doesn't require much more than wood planks, rope and a mattress (you could also use camping foam). I'm not particularly skilled with power tools, but even I could handle this, especially since many hardware stores offer complimentary cuts with a lumber purchase (because summer is more fun with ten fingers!).
The only caveat is that you have to have somewhere to hang it, which I don't, so for now I'll just daydream on. But someday, my shady naps will be taken in style.
More Info: HGTV