For many years my family owned a lakeside cabin. Our main residence was also near a lake so, needless to say, my siblings and I learned to swim rather well. One thing we enjoyed when we were children was lining up on the edge of the raft and diving into the water together. One day, at the cabin, my two brothers, their wives, and I were resting on our raft after swimming. With my SILs sitting on the far edge, my brothers and I lined up. We quickly realized that we weren't children anymore as the edge sank a few inches into the water. With a quick warning to my SILs of "hang on!" we dove off. We came to the surface to hear them cursing at us as they climbed back onto the raft. Seems the raft lobbed them into the air and into the water as we dove off. Of course, being siblings, we have the same warped sense of humor and burst out laughing which made them all the more angry, rightfully so. But it was still funny. :-)