I have had to borrow heavily from Wikipedia for this and for the love of God, do not tell me about Wikipedia not being reliable, the sources are cited at the bottom of the page.

Eid al-Fitr was originated by the Islamic prophet Muhammad. It is observed on the first day of the Islamic month of Shawwal at the end of the month of Ramadan, during which Muslims undergo a period of fasting.

Ramadan is the ninth month in the Islamic Calendar and the holiest, filled with extra prayer, fasting and charitable deeds.

The month begins when the crescent Moon is sighted, and this can vary from country to country. It ends when a month later the crescent Moon is spotted - and the festival of Eid al Fitr begins.

The day of Eid, therefore, falls on the first day of the month of Shawwal.

The date for the start of any lunar Hijri month varies based on when the new moon is sighted by local religious authorities, so the exact day of celebration varies by locality.

Eid al-Fitr has a particular salat (Islamic prayer) consisting of two rakats (units) and generally offered in an open field or large hall.

It may be performed only in congregation (jamāʿat) and has an additional extra six Takbirs (raising of the hands to the ears while saying "Allāhu ʾAkbar" which means "God is the greatest"), three of them in the beginning of the first raka'ah and three of them just before rukūʿ in the second raka'ah in the Hanafi school of Sunni Islam.

Other Sunni schools usually have twelve Takbirs, seven in the first, and five at the beginning of the second raka'ah.

According to Shia Islam, it has 6 Takbirs in the first Rakat at the end of qira'a, before rukūʿ, and 5 in the second.

This Eid al-Fitr salat is, depending on which juristic opinion is followed, farḍ فرض (obligatory), mustaḥabb مستحب(strongly recommended, just short of obligatory) or mandūb مندوب (preferable).

Muslims believe that they are commanded by God, as mentioned in the Quran, to continue their fast until the last day of Ramadan and pay the Zakat al-Fitr before offering the Eid prayers.

On the first day of Eid Muslims will wake early and attend Mosque to say prayers - one specific prayer for this occasion is known as the Salat.

Gifts are given, and often new clothes purchased in celebration of the festival.

Some of the greeting used during the day include:

“May Allah flood your life with happiness on this occasion, your heart with love, your soul with spiritual, your mind with wisdom, wishing you a very Happy Eid.”

“May this special day bring peace, happiness and prosperity to everyone. Eid Mubarak!”

“Let this Eid open your mind with new fresh thoughts.”

Kenyan celebrities who are Muslim include:

Shaffie Weru, Redsan, Refigah, Colonel Mustafa, Rashid Abdallah, Amina Abdi, Lulu Hassan etc