For a super-mini workout that you can do every day, try standing while you get dressed.
I know, it sounds too easy to make an impact, but standing while you get dressed forces your body to balance. This means that simply putting on your clothes will strengthen your reflexes and core muscles. Be careful and balance on one leg then the other, but imagine the extra strengthening you'll get from getting all dolled up by putting on your underwear, shirt, pants (or skirt), socks and shoes (tie them standing up). Try it out, I bet it's going to be harder than you think.
Fit's Tip: Bonus points if you put on tights, leggings or shoes with an ankle strap while standing up.