The Share Chair is a 2-seat see-saw-like rocking chair by the Dutch furniture and design firm Interior Tools. It's similar to traditional Chinese designs, where such face-to-face seats were common on strollers and wagons. Some came with tables like little diner booths. I'll try and dig up some pictures.
Interior Tools makes the Share Chair and a little selection of similar small tables and chairs out of recycled plastic; they call it their Black Beauties Collection. Hint: if you live in a latitude below Holland, think twice before leaving your kids' black furniture out in the sun.
It's available in the UK from their agent, Thorsten Van Elten. Apparently, though, they only accept mail order. And you have to pay with live guinea fowl.