This is mostly for those who don't the time to cook/clean during the week and still want to bring lunch (horray bento!) to work/school for health or economic reasons.
My rice cooker can churn out about 5 cups of cooked rice (about 2 cups uncooked) in 30 min. I portion them into 5 one-cup wads by lining a cup with Saran wrap (any microwavable plastic wrap will do), stuff the rice and pat down firmly before folding the wrap over it.
Then I put the wrapped wad in a zip-lock bag to lock in the moisture and throw them in the freezer and hope to the Blind Io that I don't forget about them when I run out of cookies to pack instead.
When I'm ready to put it in my bento, I just zap it in the microwave for 2 min, stuff it in my bento box and be on my merry way...