Explore | Magic: The Gathering
Formats Explore is Legal in
Official Oracle Text for Explore
Draw a card.
Official Rulings for Explore
3/1/2010 : The effects of multiple Explores in the same turn are cumulative. They're also cumulative with other effects that let you play additional lands, such as the one from Oracle of Mul Daya.
3/1/2010 : If you somehow manage to cast Explore when it's not your turn, you'll draw a card when it resolves, but you won't be able to play a land that turn.