If the “child” inside you still longs to play, perhaps you might like to check – Makedo. Makedo is a set of connectors, various hings, and a simple construction tool. The Makedo folks are “seeking to inspire social change through playful creativity”. All parts of the system are made of Nylon plastic (recycled one hopes?).
A set provides hinges (both free and fixed angle), rivet style, and a simple cut/hole making tool.
The Makedo site has a very entertaining video. Give it a watch by going to their site.
As an engineer and designer, I find Makedo a really fun and interesting concept. The basic idea is to turn ANYTHING thin (use provided tools to pierce hole or cut) into something useful for construction / design / art using provided fasteners — think Erector Set.
Lastly, where will an Open / Mashable version of this idea go?