Jnario is a framework for writing executable specifications for Java. It provides all the goodness of Xtend while being specifically tailored to writing acceptance and unit tests. It is easy to integrate as Jnario specifications are compiled to plain Java Junit tests.
PyVows is an asynchronous behaviour driven development (BDD) for Python. The main reason for asynchronous testing is to make tests which target I/O run much faster, by running them concurrently. By having a faster suite, it gets run that more often, thus improving the feedback cycle.
NSubstitute is a friendly substitute for .NET mocking frameworks. NSubstitute is designed for Arrange-Act-Assert (AAA) testing, so you just need to arrange how it should work, then assert it received the calls you expected once you're done. Because you've got more important code to write than whether you need a mock or a stub.
Midje is a test framework for Clojure. I created it to support top-down as well as bottom-up testing, to encourage readable tests, to provide a smooth migration path from clojure.test and to support a balance between abstraction and concreteness.