Rabbits and Litter Boxes

Did you know that some bunnies actually use litter boxes? Much to my regret, I learned this fact this weekend due to the party. A batch of the rabbits' guests came hopping in, and demanded use of my restroom facilities to do their bunny business. Granted, it is better than having them do it out in the yard where the neighbors could see, but still, there was a horrible line in front of the box all weekend! I thought I was going to have to take a number to get in. At least they're all asleep for the moment, though, so the box is mine until morning. I wonder if I should order a second box from Amazon? If these rabbits plan to stay around much longer, it might be needed.