Jennifer Garner [1] was all smiles while leaving the gym in LA on Tuesday. The actress beamed as she held on to a cold drink and made her way to the car. After her workout, she met up with a friend to run errands. We've seen a lot of Jennifer's big grin [2] over the past few months, especially when she's leaving the gym [3] — maybe this is what people talk about when they say exercise releases endorphins? Already this week, Jennifer has graced the red carpets at both the Teen Choice Awards [4] and for the premiere of her new comedy, Nine Lives [5]. Needless to say, she looked stunning for both events.