A business basic language called Providex (or PxPlus depending on the version).
There are several hundred thousand lines of the language in the main application where I work.
While there are definitely some major issues and pain points with it, it's actually suprisingly powerful and the language itself is still being developed.
We've got a lot of things you wouldn't think would be in a BASIC, like classes and object-oriented programming, a "UI" library that targets the web without any (tm) changes (in practice it misses that mark, but it's still extremely useful), support for the big 3 platforms, and more.
I don't deal too much with it though as most of my job is connecting new web stacks up with the pxplus backends.