jsPlumb

Graphing UI library jsPlumb - very nice.  Too cartoony for my taste, but I'm sure it's all configurable.  The point is all the heavy lifting's already done.

Declarative dataflow coding in the wild!

Wow!  The folks at Prismatic, who use Clojure to build newsfeed aggregators to spec, have developed a declarative dataflow graphing structure to describe their workflows - it's fab!

This is definitely going into Decl! I can't tell you how this resonates with what I am trying to approach.