There are two different celebrations during the Islamic calendar year, Eid ul-Fitr and Eid ul-Adha. Both of these celebrations are very important to Muslims around the world, but they are celebrated for different reasons. Eid ul-Fitr literally means "the festival of breaking the fast" and occurs at the end of every Ramadan to mark the end of our fasting. This is a joyous occasion for Muslims because it is a chance to celebrate the end of the month of fasting and worship with friends, family, and the entire community.
For the celebration, communities come together for the special Eid prayer, share meals together and participate in Zakat al-Fitr. Zakat al-Fitr (almsgiving of breaking the fast) is the obligatory charity due upon every single Muslim (regardless of age, gender or income) at the end of the month of Ramadan, and must be paid before maghrib of the last day of Ramadan, or before going to the Eid prayer on Eid day at the latest. Traditionally, Zakat ul-Fitr is one sa' (i.e. a volume measure equivalent to four double-handfuls) of a staple food of any given area (for instance, a sa' of rice, dates, wheat, barley, etc.). Most contemporary scholars have agreed that the payment of Zakat ul-Fitr can be the equivalent value in money for any specific local area. Check with your local mosque and follow their guidelines regarding when to pay and what to give insha'Allah.