In addition to HN (as noted by my sibling) Facebook has extended both PHP and JavaScript with their own DSL's and syntax. I'm sure there are many more, but a lazy comment deserves a lazy answer ;)
Using DSL to describe your domain (application) is normal. One application = one domain.
Learning in addition 15 different DSLs for libraries and tools, just because it's cute, is not the way to go. Soon you will argue about the exact definition of monad instead of shipping code.
