Visit this link at Runner's World for an awesome workout for runners and really anyone. The workout hits all of the body and only takes about 30 minutes. Check out the site and watch the videos on each exercise. I have done most, if not all, of the exercises and like the sequence this article puts them in.
The great things about this workout include the following:
1. You don't need to go to a gym!
2. All you need, a yoga ball, a kettlebell (or single heavy dumbell), & 2 dumbells.
3. Works the whole body.
4. Doesn't take forever.
5. It has a lot of balance related exercise, good for everybody.