At our home we regularly eat leftover cold rice the next day with breakfast or lunch. The trick is to be sure that it is not exposed to air and not refrigerated. We leave it in the pot that it was prepared in, being sure to keep it covered/sealed. It stays perfectly good through the next day - in fact we usually don't take it out and put it into a container for the fridge until the next night's meal. Additionally, I also shake off the condensation which gathers on the lid after cooking. I'm not sure if it does anything, but I feel that excess moisture may lend to faster spoilage.
It should be noted that this is using Japanese/Korean rice which usually a medium grain Calrose rice which characteristically softer and stickier than Chinese or other rices. I can't say what the results are like for other drier rices.
Also, if you use the type of cooker that has a warmer control on it, Japanese/Korean households leave it on constantly so that warm, if not hot rice is available at any time, so that they are able to pack rice while it is still warm in the morning for the day's lunches. Maybe you might want to invest in one of those...
It has been my experience that adding water before microwaving helps it to spoil faster if it is not used up completely (eaten). The best method for reheating leftover rice is to heat it sufficiently - approximately 1:30 mins per cup - covered and without adding water. (This is also the time instruction for pre-cooked rice available in individual servings packages in stores.) It comes out like freshly cooked. Well, nearly.
Putting leftover rice in the fridge immediately makes it hard, which is easily remedied with a microwave, but when it's not available as the OP stated, the above method works for me.