As the year grows colder and finally dies, each Seeker examines whatever spiritual progress he has (or has not) made in the preceding year. Revelations Day, also known as Ascension Day, offers every member of the faith the chance to take back a portion of what he has given throughout the year, and to reflect on the insights so gained. During the Revelations Day ritual, the ritemaster convenes the assembled Seekers for a Sacrament of Blood. This time, though, the ritemaster conducts a magical ceremony over the filled chalice that simultaneously cleanses the blood of impurities while concentrating the life energies inherent within the precious liquid. (Secretly, it is often mystically altered in other ways, depending on the ritemaster’s orders.) When this ceremony is complete, the ritemaster passes the chalice around once more, with each Seeker drinking from it in turn, taking back no more than he had put in. This ingestion always results in a mind-altering episode whose duration and intensity varies with the individual, and to a lesser extent, the amount consumed. These “blood trips” offer faithful souls the chance to visualize the truths that lie within not only their own blood, but within that of their fellow Seekers.
Source: Faiths of Eberron
Also called Ascension Day, this ceremony allows Seekers to meditate on their spiritual progress. Seekers gather for a Sacrament of Blood; once the chalice is filled, the priest conducts a ritual to purify the blood. (On rare occasions, some priests secretly alter it in other ways as well, depending upon their ambitions and abilities.) The chalice is then passed through the assembly, and each Seeker takes a sip. The result is a religious trance during which an imbiber experiences visions and waking dreams; these experiences are said to impart some element of truth or revelation about the Seeker’s life, faith, or future, but only if the Seeker interprets the visions properly
Source: Eberron Campaign Guide