Text (DK+errata): Spells you cast cost up to {1} less to cast. [Oracle 2009/07/08]
Does not change the cost of the spell, it just pays part of it for you. [bethmo 1994/09/22] So the cost is still the full cost for reasons of Spell Blast of other such effects. [D'Angelo 1998/02/03]
Only contributes one colorless mana toward the spell mana cost. This cannot reduced your payment below zero even when combined with Mana Matrix or Planar Gate. You must always pay the colored mana part of the spell cost. [bethmo 1994/08/10]
Only contributes to the generic mana portion of a spell's cost. If the spell does not accept generic mana or accepts less than {2}, you get a reduced or null effect from this card. [Aahz 1994/12/06]
You can choose not to use the Calendar's bonus. [D'Angelo 2008/12/20]
Extended tournaments (see Rule 913) have banned this card since 1999/10/01.
