I've been hearing various rumbles about this for a few days, but as Nick Confessore notes the draft is about to be underway. The military is tracking down members of the Inactive Reserves - as I understand it, basically former military personnel who have their names on file just in case of emergency - and telling them they may as well sign up now.
In addition, according to military.com, the military is apparently using the IRS to track these people down.