A piece of fun trivia. What is currently the PostgreSQL codebase used to be written in Lisp, and was subsequently ported to C.

You can still recognize Lispy idioms in many places, there's abundany usage of the List structure, functions called lcons and list_head/list_tail and a NIL constant for an empty list.

See the anecdote at line 77 in a README file: http://git.postgresql.org/gitweb/?p=postgresql.git;a=blob;f=...

I like this one.

I read about writing DSLs in Scala and then tried to backport as much as I could to good 'ol Java.

Now I write Java that looks like it's half LISP and half COBOL and I'm pretty happy with it, I don't even complain about null.

And any sufficiently well-documented common lisp program contains an ML program in its comments. [not mine, can't remember who said it]