The significance of Poya days

In Sri Lanka, Poya full moon days are holidays. On such days, the sale of meat and alcohol are forbidden. In my visits to Sri Lanka in the past, I noticed that regular television shows are either paused or skipped and Dhamma talks are broadcasted in most channels. Many people go to temples and follow the eight precepts. Poya is a Sinhalese word, that comes from the Pali word Uposatha meaning "to fast". Many of these full moon days occur every month and signify important events during the Buddha's time and during the dispensation. Sometimes a full moon can occur twice a month. In the image below the list of full moon days are mentioned, and the reason why they are commemorated.

Note: The poya day in Novemeber is Ill/il in case you were wondering. The letters seem identical.

Source: http://www.srilanka.travel/srilankan_public_holidays

Image: http://www.deviantart.com/art/Full-Moon-113210615