Time to try some more creative stuff with my camera, particularly some long-exposure night shots, with the help of a tripod. Here are the best 3:
Compare with this photo which I've since discovered on flickr, taken by Greenbelt official photographer Jonathon Watkins:
I don't think I did too badly: firstly I thought of the same shot (just about), and I fiddled around to get about the same effect. He used a stepladder, or else he's a giant, and used a shorter 1.3s exposure rather than my 3.2s one.