I've got to admit, I've got my reservations about Boo. There's the take-up question, which wasn't a big deal before the DLR came striding into town, but is much more important now that there are other ways to skin this particular cat. Then there's the extensible syntax, which is one of the most powerful shotguns I've ever seen. They've even helpfully set it up to point at your foot by default. Fact remains, I've just done some work for the Castle project that uses Boo for its DSL. Again, I've gone for the "just get it working" approach, so...