Cider is great. But...
As a beginning Clojure user Nic found he wanted to run the whole program. Not rely on a relatively complex workflow to reload classes. Also it seemed the right thing to do to him.
So this let's you run lein or run a lein repl in a process and interact with it.
Nic has never liked ielm or any of the comint modes so this also has a basic command line interaction implementation. The lein process output is piped into a buffer and a fixed point at the end of the buffer is used as the prompt. A simple keymap hanging off a prefix key ("#" currently, "##" will insert a "#") is used to allow scrolling up and down through the history.
The command line has smartparens support but no completion.