Six Days of Shawwal

Abu Ayyub al-Ansari (may Allah be pleased with him) narrated: Allah's Messenger (peace be upon him) said: "He who fasts Ramadan, and six (days) of Shawwal, it will be (equivalent to) as if he fasted a whole year (in terms of rewards)." (Reported by Muslim, at-Tirmidhi, Abu Dawood, Ahmad, Ibn Majah)