I'd recommend fitness hula hooping. Preferably using a weighted hoop with a large diameter depending on your size (38 inch diameter was a good size for me to start on, with an approx 31 inch waist). The smaller the hoop to waist ratio the more challenging you will find it. Sorry I can't recommend a US supplier as I live in the UK.
Hooping is great fun, excellent for the waistline as it tightens the abs, and a very good mood enhancer.
Not sure how primal it is considered to be, but it does have a 'dance feel' to it, and dance is certainly primal.
I've been amazed at how quickly I've progressed with developing tricks, which makes it very rewarding.
Yoga and light dancing are also easy enough to do at home (I'd recommend using a video guide if you've not tried yoga before). Yoga is great for mood and the immune system. My pet rabbit has a small repertoire of yoga moves so I say that makes yoga primal!
F 5 ft 3. HW: 196 lbs. Primal SW (May 2011): 182 lbs (42% BF)... W June '12: 160 lbs (29% BF) (UK size 12, US size 8). GW: ~24% BF - have ditched the scales til I fit into a pair of UK size 10 bootcut jeans. Currently aligning towards 'The Perfect Health Diet' having swapped some fat for potatoes.