Balance, clutch and brake control = trials bike. They are alot of fun and the practice/skills you get from riding them transfers to heavier bikes. You can try/learn to do wheelies, hops, balance at a standstill and other silly things w/o too much risk. Ride one if you can. Mountian bikes (bicycles) can do much of the above for you too, may not be quite as much fun but might be good for your fitness level. Exercises can do alot for your balance and fitness. Toys like Bongo boards, Bocee balls will do the same.