Lego-style BrickCase for iPhone 4 and iPhone 5
Not just Lego though, this case is apparently 'compatible with all major brick brands', should you want to use your case as the basis for your next construction job.
But essentially, it's a piece of quirky design (and protection) for your iPhone, available in a variety of colours. See all those colours on the retailer's site, where you can buy one for £19.99.
BrickCase for iPhone 4 at Firebox
BrickCase for iPhone 5 at Firebox