Perhaps taking a lesson from Allen, I built a couple Adirondack chairs last week.
I did go sort of against tradition, though - instead of 'lightweight and airy', mine are stocky, blocky, and heavy.
I had a cheapo plastic 'Adirondack style' chair that I found comfortable, so I copied its dimensions in these.
Since they'll remain outside 24/7/365, I made them from pressure treated wood. 4X4 front legs, 2X8 seat supports/back legs and 5/4 decking for the rest. Very heavy, but they're not likely to either blow over in a moderate wind, or sink too deep into the ground.
They're drying out in the sun right now. I'll sand them down in a week or so, then let them 'weather in' for a couple months before I put any kind of a sealer or finish on them.