I am current on the path of becoming ambidextrious, here are a few benefits I can think of:
more focus/concentration, intelligence, coordination, less physical limitation, more effecient, supposedly the brain actually grows and to tell you the truth sometimes it feels like it does.
Im assuming your right handed when I say use your left hand mmkay.
So what can be done to establish this fine trait?
Do everything with the left hand, this seems obvious but its easy to forget. Do things like put your computer mouse on the left side. Go buy left handed scissors.
Learn to juggle, this also improves coordination, reaction time, catching ability, timing, rhythm and if you add arm weights taadaa, physical strength and endurance.
Learn the piano, gives all noise more beauty, including silence, coordination, memory, timing, rhythm, improves ability to visualize, improves singing ability.
Learn the drums, increases physical strength, massive coordination, rhythm, super fun.
Draw with the left hand, you can also draw with your right at the same time, hell different pictures. Or you can draw a butterfly symmetricly with each side doing its part.
Write with your left hand, cursive, print, write down all the amazing things you will do when your ambidexterous.
Write with one hand / draw with the other? im not sure if its possible, but why not super charge your brain.
Learn to "keep up" with a soccer ball or hacky sack, your feet need training too, plus its cardio training. Add leg weights and oh man, lower abs of steel. (the 8 pack)
Stir two cups of water in opposite directions, alot of these things will tear your brain apart... dont worry its like muscle and helps it grow(we hope)
Left handed cartwheels, they are fun so whatever.
Play Left brain right brain for Nintendo DS, dont play it right handed though.. and try to get it for cheap. Actually instead play all DS games with opposite hand.
Kongregate.com, computer games with the left hand are super worth it. Cause they are also GAMES! but dont get distracted.
Rubs your hands clockwise, your feet counterclockwise, at different speeds too! its tough. its best to do it on your back.