Racquetball

My son and husband have enjoyed playing racquetball together at the Downtown Oakland YMCA, but we won't be able to keep our membership there much longer. Do you know of anywhere they could play racquetball on a drop in basis? With our busy schedules it doesn't really make sense to pay for a membership somewhere since they don't have time to go all that often, but would like to have the option when it does fit in the schedule.

Thanks