Knowing the Unit Circle is CRITICAL for success this semester in Precalculus. Here are a couple of sites that might help you practice learning it!
http://www.purposegames.com/game/angles-of-the-unit-circle-radians-quiz
http://www.sporcle.com/games/talbr6/fill-in-the-unit-circle
http://cs.bluecc.edu/calculus/TrigTools/Files/UnitCircleValues/FunctionValues.htm