Terra is a new low-level system programming language that is designed to interoperate seamlessly with the Lua programming language
I like the name, because it is in fact the terrestrial, lower-level counterpart to the lunar, higher-level Lua. Some things about it:
it's a statically-typed, compiled language, hence the low-level part
can call Lua functions from Terra code, and vice-versa
can use Lua to metaprogram Terra programs (conditional compilation, templating)
it's trivial to import and use C functions/libraries (as well as Lua)
like Lua, can be relatively easy to embed in applications
I think this thing has a lot of promise. Ever since I heard about it I've been a bit excited. Although I'm sure there is, I can't recall off the top of my head two or more languages with this kind of synergy.