There are a lot of languages that are actually pretty small if you just boil them down to their primitives. Prolog and most other rule engines, especially CLIPS, jump to mind. ANSI C and SML. SML in particular is cute if you use your tiny Prolog to implement the type system ;-)
I do not. As far as I'm aware, SML is much like C in that despite being a relatively simple language, there aren't many toy implementations floating around.