exercism.io has been very useful for learning Clojure so far. The exercises are not excessively difficult, like the ones in Ruby Quiz (which are great btw).
Given the fact that each exercise comes with unit tests and that I'm
used to TDD, I added the humane-test-output dependency and
lein-auto plugin to each exercise for improved developer experience.
Inside each exercise root folder, run lein auto test to watch files
and re-run tests automatically.