Lambda the Ultimate

In short: take Scheme, remove mutations, add isolated processes with mailboxes, add message sending and receiving operations and an addressing mechanism.

Termite is a Lisp for distributed computing (PDF paper and PDF presentation), providing an Erlang like model on top of Scheme.

As the presentation says, the powerful abstraction facilities provided by Scheme made impelementing Termite rather easy and the implementation doesn't require much code.

[Edit: here's a working link for the PDF paper]

I think that diagram-based languages could be useful someday. So, here they are, The DiaGen - Diagram Editor Generator and Diaplan - a language for programming with diagrams.