Ask HN: Starting with Lisp

I've read a lot of good stuff about LISP (in general common lisp) and would like to play around with it in some toy projects.

Does the flavour of lisp matter much? (Common List, Scheme, Racket, Clojure)

What's a good environment to start programming in LISP on a Mac? (IDE)

Any resources you'd recommend?

Thanks in advance!