The Spec# programming language
I'm working on my MS Thesis project (I hope to post more on this soon) and I
came across Spec# which
is a new programming language that is being worked on by Microsoft Research.
Spec# is a superset of C# that adds things like non-null types, checked
exceptions and contracts (i.e. pre and post conditions and invariants).
If you are interested in Formal Specifications or Design-by-Contract then you
might want to take a look at the Spec#'s research group publications. There are very
few publications right now but I suspect there are more to
come.