To play with one of the examples, start the REPL and load the appropriate namespace.
lein repl
user=> (use 'clojure-actors.ping-pong)
user=> (ping-pong 10)
user=> (use 'clojure-actors.sleeping-barber)
user=> (sleeping-barber 10)
user=> (use 'clojure-actors.dining-philosophers)
user=> (dining-philosophers 5 3)