One of the best way to get some exercise is to "wear" your baby. Henry and I grab our carrier and go on daily walks. Usually they range from 10-30 minutes, depending upon the weather and how Henry is feeling. Some days we may even take more than one. One thing we also will add to our walks is other mini routines.
Some of the exercises we will include are squats, lunges, side shuffles, football runs, etc. Usually we stick to lower body work, however arm exercises can easily be incorporated into your baby wearing routine. I find that carrying Henry gives me the best arm workout, so when I'm wearing him I usually focus on my lower half.
Below are some video examples: