It is Pchum Ben at the moment in Cambodia. The Khmer people believe that this is a time when the spirits of dead ancestors walk the Earth. And the living can ease their suffering by offering them food to eat. Early in the morning (4-5am) on the fifteenth, and last day of the festival, Cambodians go to the pagodas and throw balls of rice over the walls for the dead to eat. By easing the suffering of the ancestors, they help them back into the cycle of reincarnation, and thus enable them to obtain good kharma in a future life.
This is a big national festival, and means that work stops and people go back to the provinces to see their families for several days. It is probably the equivalent of Christmas or Easter for those of you from traditionally Christian countries. It is a time of reunion, both with the dead and the living. There are 15 days of eating, drinking and celebrating with family and friends.
Despite not being a Buddhist, I will be using this time to remember the people I love who have passed away and hope they have managed to achieve some form of peace.