World Council of Churches' Ecumenical Prayer Cycle. This changes weekly and cycles around the world once a year. It is linked to a WCC publication In God's Hands: The Ecumenical Prayer Cycle.
The full cycle is laid out on the Ecumenical Prayer Cycle page of the WCC website. They say:
At the very heart of the ecumenical movement is the reality of prayer. Jesus prayed that we may all be one, united in God in the mystery of the Trinity. That is the basis and the goal of our search for unity.
The Ecumenical Prayer Cycle enables us to journey in prayer through every region of the world and through every week of the year affirming our solidarity with Christians all over the world, brothers and sisters living in diverse situations, experiencing diverse problems and sharing diverse gifts. Lord, hear our prayer ...
It is possible to install the cycle into your own blog, website or Facebook page. Instructions can be found on the WCC website. It is also possible to submit your own prayers for use in the prayer cycle.