By the way, I HATE the newest, cutsie, pretentious word - "up cycle" - you're being creative and reusing what would otherwise be called JUNK/TRASH! Repurpose / recycle - just call it that! Up-cycle is putting lipstick on a pig!
Wood crates can be found in many home. They are perfect for making of all kinds of furniture. Take a look at these DIY wood crate projects, which are so versatile, functional and decorative for your house and yard.