Hey, what's the big idea? Lego and ad agency DLKW Lowe created some fun mini-billboards touting a new hotel and other attractions at the Legoland Windsor resort in England. The 12-inch-high signs, made of Legos, were placed around London, and folks spotting the small wonders—guided by Google Maps—could share photos on Twitter using a special hashtag. That social engagement, plus ample free media coverage, maximized the campaign's reach to impressive proportions. (In fairness, it should be noted that Deutsch/LA went big with small ads first in its 2008 campaign for the video game LittleBigPlanet.) Still, nice work, blockheads! More images after the jump. Via PSFK.