A couple of the scientists who work at the Large Hadron Collider got together and designed a model of their accelerator made from LEGO bricks.
Their goal is to get enough people to support the design that the company begins to work on it officially and then may actually offer the kit for sale. But, as the story on Physics World's blog notes, you can also download a set of the instructions which tells you what kind of pieces you need and shows you how to build them.
I kind of hope they get LEGO to sign off on the project, because this would make one cool offering in the LHC gift shop. If the LHC has a gift shop, that is.
I would advise against LEGO offering a powered model of the collider, though. Just because it's smaller doesn't mean it can't create a black hole that would destroy the universe.