Pope Francis has called for everyone to pray for peace, Saturday, Sept. 7. In the Eastern time zone of the US, pray especially from 1 pm to 6 pm. 
Some ideas for prayer and fasting here.
Vatican vigil schedule here, from Deacon Greg at Patheos.
(Graphic here from https://www.facebook.com/CatholicPulse, photo credit CNS).
Forma Fidei 