There are many things you can do...just make sure to keep your heart rate under 140, do the "breath" test. If you can talk to a friend normally without huffing and puffing, you're not overdoing it and should be fine. Take it easy on the joints and on any jumping type exercises, i wouldn't do anything like that without discussing it with your doctor. Spinning, cycling, walking, running if you've been doing it regularly before getting pregnant, yoga(prenatal), pilates(prenatal), strength training(don't lift anything too heavy), belly dancing, and any of the prenatal cardio stuff should be just fine. If you have any concerns at all, discuss it with your doctor first!