These days there is quite some buzz around the LichtFaktor crew, a group of German light graffiti artists, whose work is rather impressive.
Color + Design blog has an interview with them, where they share some insights about their technique.
Below you can watch a video called Star Wars vs Star Trek they have been recently doing in the UK for Sky Movies.
And if you're interested in the commercial side of light graffiti, have a look also at Vincent's blog, where he talks about a recent Sprint campaign in the US.