Yoga will not only make you have strong, lean muscles, but it also is a great de-stresser. 

Great for in the morning, or a pick me up anytime throughout your day. Repeat as many times as you have time for 

Yoga with a friend is more fun, and still beneficial. 

Some yoga videos:

http://www.youtube.com/watch?v=b0Bc91_ws94&list=PL39D531F79884A5F0&index=4&feature=plpp_video

http://www.youtube.com/watch?v=lvCiVsER-Cs&feature=bf_prev&list=PL39D531F79884A5F0

http://www.youtube.com/watch?v=9z2vSwHE0lI&feature=bf_prev&list=PL39D531F79884A5F0

http://www.youtube.com/watch?v=X0pZUjXGq8w&feature=bf_prev&list=PL39D531F79884A5F0