I do like the idea of art on the freeway underpasses, but I have reservations about graffiti. I would rather see murals, or some kind of compelling imagery (think Bansky) rather than stylized lettering and that kind of thing. I guess it just depends on what type of imagery it is, but yes, art on the underpasses would be awesome!
We have the Saturday Strolls, which I love. I like being able stroll around without a big crowd, and though the hours don't run late, they work for me .