Rulings

• 2014-02-01
  Courser of Kruphix doesn't change when you can play lands. You can do so only during your main phase when you have priority and the stack is empty.
• 2014-02-01
  Playing a land with the second ability counts as your land play for the turn. If you play a land from your hand during your turn, you won't be able to play an additional land from the top of your library unless another effect allows you to.
• 2014-02-01
  The last ability triggers whenever a land enters the battlefield under your control for any reason. It triggers whenever you play a land, as well as whenever a spell or ability (such as Rampant Growth) causes you to put a land onto the battlefield under your control. It will even trigger when a spell or ability causes another player to put a land onto the battlefield under your control (as can happen with Yavimaya Dryad's ability, for example).
• 2014-02-01
  While playing with the top card of your library revealed, if you draw multiple cards, reveal each one before you draw it.