What are some good at-home exercises I can do at home that I can involve my 5 year old in?

Dance. 5 year old love music and dance. Zumba hula are also fun. Wii or kinect if within your budget is also another in home way to exercise. Make routines short 10 mins max but you can continue and include him in intervals for max of 30 mins.
5 year old exercises. Kids this age are learning to hop, skip, and jump forward, and are eager to show off how they can balance on one foot (for 5 seconds or longer), catch a ball, or do a somersault. Preschoolers might also enjoy swimming, hiking, dancing, and riding a tricycle or bicycle with training wheels.