Gosling on Closures
I think he makes an important point that there are a set of features including closures that Neal has been talking about and they are inter-related. It seems to me that along with closures, stuff like extension methods and chained invocation are likely important counterparts, not just random interesting ideas. Of course, a simliar thing happened in Java SE 5, where we saw things like variable args, enums, generics, static imports, autoboxing and annotations could support each other in different ways where it was necessary.
Hopefully, the closures and other language work will move along quickly enough that library JSRs can take advantage of the same facilities.