Check out this company's website. They produce moulded resin connections that enable you to create picnic tables and benches, shelving, workbenches, outdoor storage buildings, and more with simple lengths of 2 x 4 wood boards. No complicated sawing or angles- you just slide in the lumber and attach with bolts.
I saw a picnic table made of this material at a rest stop in Wisconsin and it was an attractive, simple piece of furniture built to last. I'd also bet that the bracing materials are recycled plastic.
Per the site, these components are available at Menards, Mills Fleet Farm, and Northern Tool and Equipment.
Lawn furniture for dummies! What a concept!