What Even Is a Lectionary?
This lectionary provides a three-year series of readings for Sunday starting with the season of Advent, four weeks before Christmas Day. For each Sunday and festival, three readings and a psalm are suggested and include: a Gospel reading, an Old Testament reading, and a New Testament reading. The lectionary is a work of The Consultation on Common Texts, an ecumenical consultation of liturgical scholars and denominational representatives from the United States and Canada, who produce liturgical texts for use in common by North American Christian Churches.
Each year of the Revised Common Lectionary centers on one of the synoptic Gospels — Matthew, Mark and Luke. The Gospel of John is read periodically in all three years and is especially frequent in Year B.
… The daily readings provide a psalm and two Scripture readings for each day between Sundays. The foundational premise of this set of daily readings is their relationship to the Sunday lectionary. The readings are chosen so that the days leading up to Sunday (Thursday through Saturday) prepare for the Sunday readings. The days flowing out from Sunday (Monday through Wednesday) reflect upon the Sunday readings.
The Vanderbilt Divinity Library has some great resources for the Revised Common Lectionary, including calendars that you can subscribe to in Google Calendar, iCal, and Outlook as well as an RSS feed for the daily and weekly readings.