Tarawih
Tarawih (تراويح) is an Arabic phrase referring to extra prayers given at night in the Islamic month of Ramadan. Tarawih prayers consist of (8-) 20 raka'ahs. It is normal to attempt to recite the whole of the Qur'an during Ramadan. This is done by reciting one juzu each night or in each tarawih by dividing the juzu into several ayat recited in one raka'ah. Tarawih can be performed at home if one cannot attend the mosque one day. If someone does not know how to read Qu'ran or cannot read it very well, he/she can recite Surahs that he/she knows.
Tarawih was originally instituted by Umar ibn al-Khattab, the second Sunni Caliph. Several hadith reports say that the Prophet Muhammad often offered these prayers during Ramadan.
The Shi'a do not perform Tarawih.
Though tarawih prayers are offered in Muslim communities worldwide, in the diaspora (North America, Britain, etc.) they are important congregational events for both men and women. In Muslim countries where women do not attend mosques regularly, they tend to pray tarawih at home, while in the diaspora it is common for women to attend tarawih prayers at mosques. (Note: women do NOT uniformly refrain from attending mosques all over the Muslim world).