World Communion Sunday is celebrated on the first Sunday of October. It originated in 1936 in the U.S. Presbyterian churches; from its inception, it was intended as an interdenominational expression of fellowship in Christian faith. Since then, the observance has spread to many other sects; Methodists, for example, number World Communion Sunday as one of the "Special Sundays". As the name suggests, it is marked primarily by the sacrament of communion.

While the Christian tradition of communion (or Eucharist) is rooted in the account of the Last Supper, the element of bread also enjoys a rich significance reaching even further back in Judaic tradition. Just as everybody needs food, so too is every soul (Christian or otherwise) nourished in fellowship. The World Communion observance calls Christians to reach out with forgiveness, tolerance, and charity, not only to their Christian fellows, but to all people.


Sources:
"World Communion Sunday 2002", http://www.ncccusa.org/ecmin/worldcommunionsunday2002.html, National Council of Churches.
King James Bible, Matthew 6, 18, and 26