How to get volunteer experience?

I have just about finished all my pre-reqs except for Micro, and I'm ready to apply for nursing school. The only thing I'm missing is medical/volunteer experience. The problem is that I'm so busy I can't fit it in! I have school work, a job and 6 kids. When I start nursing school I will cut back on some things but I can't cut back now in anticipation of nursing school.

I went to one local hospital, filled out a volunteer application and on the cover it said not to apply if you can't commit to 100 hours over the next three months. I think that's quite a heavy commitment to ask of a volunteer. My SIL used to visit patients at a nearby hospital/nursing home and she said not to bother volunteering; she said she would just show up, walk through the floors and do whatever needed to be done. Security in this hospital must be pretty lax if she was allowed to just wander through at will, but I really wouldnt' be comfortable going in unofficially and anyway it wouldn't help me much in terms of getting a recommendation for nursing school, if my volunteer work wasn't coordinated with the hospital.

Does anyone have any ideas? I need some volunteer experience that involves patient care but is flexible in terms of the hours and days.