(1) To bear witness that there is no entity worthy of worship except Allah(God) alone, and that Muhammad (pbuh) was His messenger. This establishes obedience to God Almighty alone.
(2) To perform five prescribed prayers to God every day according to a specific prescribed method and at specific prescribed times. This continually reminds us to bear God in mind in all actions, either before or after any given prayer.
(3) To pay two and a half percent (2.5%) of ones wealth to charity every year if their savings exceed a certain minimum level which is considered above the poverty level. (This is the basic concept, the actual calculation is a little more complex).
(4) To fast the month of Ramadhan (from the Islamic Lunar calendar) every year from sun rise until sunset. This involves not eating, drinking, or having marital relations, from sun rise until sun set.
(5) To perform a pilgrimage to Makkah (in the Arabian Peninsula) once in a Muslim's lifetime if it is financially possible and their health permits. During this period, Muslims come from all over the world to join together for six days in a prescribed set of acts of worship. All Muslim men are mandated to wear the same garment which was designed to be very plain, simple, and cheap to obtain.
Mu'ad ibn Jabal said: I said to Allah's Messenger (peace be upon him): Inform me about an act which would entitle me to enter into Paradise, and distance me from the Hell-Fire. He (the Prophet) said:
"You have asked me about a matter [which ostensibly appears to be] difficult but it is easy for those for whom Allah, the Exalted, has made it easy. Worship Allah and do not associate anything with him, establish prayer, pay the Zakat, observe the fast of Ramadhan and perform Hajj to the House (Ka'aba)." (Narrated by Ahmed, al-Tirmathy, and ibn Majah)