i've taken both yoga and aikido (classes at the Y are inexpensive - even for non-members) and i miss both of them...would like to get back into them...especially yoga.

yoga was very relaxing and is all about strengthening muscles and increasing flexibility. after two sessions i noticed a difference.
aikido was fun for me. it's not high energy but is quite physical. i always felt refreshed after class.

dunno if that says much...could tell you more another time if you'd like.