Issues is a project mainly written in Ruby, it's free.
A command line interface to github issues with offline support
$ issues init # initializes an issue tracker for each github remote
$ issues trackers # lists issue trackers
$ issues use <tracker> # sets the active issue tracker to be "tracker"
$ issues pull # pulls latest issue info from each remote tracker
$ issues push # pushes local issue updates to remote tracker
$ issues status # pushes
$ issues ls # lists open issues
$ issues ls --all # lists all issues
$ issues ls --mine # lists all issues that are assigned to me
$ issues ls --closed # lists all closed issues
$ issues ls <label> # lists all issues labeled with "label"
$ issues label # lists all labels
$ issues show <issue_number> # shows issue description
$ issues log <issue_number> # shows all comments on the given issue including the discription
$ issues comment <issue_number> # opens $EDITOR and lets you comment on an issue
$ issues comment <issue_number> -m <message> # same as above but supply comment inline
$ issues close <issue_number> # same as `$ issues comment`, but also closes the issue
$ issues close <issue_number> -m <message> # same as above but supply comment inline