For new users of Clojure, it is very hard to find out that evaluation results in any Clojure REPL are bound to *1 - *3 and the latest exception to *e. Since it is a pretty useful feature, it should be documented at a visible place. Where that place is, I am not sure.
One possibility would be to add it to the docstring of clojure.main/repl and make http://clojure.org/repl_and_main link to it (i.e. in the "Launching a REPL" section, we could add something like "Read the <link to=somewhere>docstring of clojure.main/repl</link> to learn about options and available vars. See also utility functions/macros in the clojure.repl namespace."
Note: This was originally reported under nREPL in NREPL-43.