Kicked off on 6th October 1973, the Jewish holiday of Yom Kippur. Now the odds against the Yom Kippur war starting on Yom Kippur must be massive! Well, 365 to 1 anyway. Not as odd as the Battle of Hastings being at Battle, near Hastings, but still. Makes you think.
Anyway, the usual suspects in any Middle East war were involved. Egypt and Syria decided to cross into the Sinia and Golan Heights which they had rather carelessly lost in the 6 Day War of 1967.
It all went well for Johnny Arab for the first couple of days, but then the IDF got its act together, stopped the Ragheads and pushed them back out again.
Anoraks enlarged at this wiki page.