Text (MM+errata): Players can't cast spells with the same name as a nontoken permanent. ; Players can't play nonbasic lands with the same name as a nontoken permanent. [Oracle 2009/07/08]
This card only looks at cards in play, not ones on the stack. So it is possible to play two instances of a spell onto the stack. [MM FAQ 1999/09/22]
Does not prevent effects which "put into play" a card. It only stops people from playing (announcing). [MM FAQ 1999/09/22]
