At the Olympics in London going on now, different countries have "national hospitality houses", set up to entertain athletes and other visitors. The Danish hospitality house is called "Imagine Denmark" and is at the St Katharine Docks. Since Denmark is the home of the LEGO Group, it is not surprising that they have several LEGO-themed events and exhibits. One that has received a lot of attention is a LEGO replica of the Olympic Park by Warren Elsmore.
The Imagine Denmark information page also told how Aug. 4 and 5 would showcase "Danish Fun and Games", in which "Children of all ages are invited to two days of building fun with LEGO bricks, competitions, exhibitions of the stadiums in Stratford and a seven-metre tall LEGO wind turbine – the world's tallest Lego wind turbine. We are also welcoming visitors to help building the famous Danish Skagen painting "Hip Hip Hurra" in Lego mosaic bricks." That sounds like a fun weekend!
I haven't yet seen a photo of the Hip Hip Hurra painting mosaic, but I did see photos of this almost-finished Olympic-sized mosaic of a world map done by Bright Bricks.
Bright Bricks is a company run by the U.K.'s only LEGO Certified Professional, Duncan Titmarsh. Brickset did an interview with him once, which you can read here.
You can find photos of the world mosaic in various stages of completion at Bright Bricks' Facebook Page. Some of the detail shots are really neat: