CNN

* Sen. John McCain and Sen. Barack Obama are at Ground Zero for a ceremony to mark the 7th anniversary of the September 11th attacks. Both candidates later speak at the Service Nation Summit Presidential Candidates Forum at Columbia University. Earlier in the day, Sen. Obama has a working lunch with Former President Bill Clinton.

* Gov. Sarah Palin attends her son Track’s deployment ceremony near Fairbanks, Alaska.

* Sen. Joe Biden holds a discussion with First Responders in Parma, Ohio.