I just found this great blog post on the MoMA-blog. This is what happens when you give MoMA-employees a Friday afternoon with Lego; they start copying the art!
My favorite was this yellow piece that they have made. It is probably the most complex of the pieces, so you can imagine that most pieces are quite simple, but so are the artwork that they copy. (You will have to go to the MoMA-blog to see the other photos.)
I would love to see an exhibit at MoMA just with Lego art. The Lego company should just send loads of Lego bricks to artists to see what would come of it.