Alors, cest la guerre! can be translated as "Then it is war!"
Greece's main public event in October is Oxi Day, on the 28th. Oxi, by the way, means 'no' in Greek. This day commemorates the date in 1940 when Greek dictator Ioannis Metaxas said no (actually, he said "then it is war") to the Italian demand to march unopposed into Greece. This was Greeces entry into WWII on the Allied side. Greeces fierce resistance against Italy and then against the Nazis is a source of Greek pride.
Most towns have parades on October 28th. School kids get to march in front of their parents and everyone else. We saw kids practicing in Kardamyli earlier this week. Military parades also occur in the larger cities. The day is a public holiday and all state and most private offices are closed. In tourist areas shops and restaurants shut for half a day so their owners can go watch their kids march, but most have reopened by the late afternoon.