Once you've started tracking some metrics there are several ways you can read their values.
More reporting methods will be added in the future. Pull requests are welcome.
metrics-clojure supports reporting metrics through the console (on standard error):
(use '[metrics.core :only (report-to-console)]) (report-to-console 10)
This will tell metrics to print all metrics to the console every ten seconds.
JMX and jvisualvm
metrics-clojure also supports JMX reporting, since it's built into metrics itself.
In a nutshell: you can open jvisualvm (which you probably already have as it's included in many Java distributions), connect to a process, and view metrics in the MBeans tab.