When I was frustrated with depression, I rolled up a piece of paper and threw it into the living room. I repeated it again and again as my frustration was building up. Also, I rolled up newspaper and junk mail, and added them to the pile.
The rolled-up paper accumulated over a period of about 3 weeks to form a mountain of about 2 m in height. When my kids saw it, they immediately jumped into the "newspaper pond". They kept playing completely immersed into the newspaper pond. They even wanted to sleep inside! It is like playing in a pile of maple leaves, but they can play in the newspaper pond year-around, not just a few weeks in the fall.
I jumped into the newspaper pond myself, and found that it is fun for adults, too! You can literally jump into the newspaper pond without feeling any pain at all, while the rigid plastic balls in the IKEA Ball Pit would hurt your body if you jump into it. The only problem with the newspaper pond is the black ink on your clothes, but the soy-based ink washes out all right. Some newspaper companies give away end-rolls of unprinted newsprint.
It is recommended that the rolled up paper be piled up on a carpeted floor rather than on a hard floor, just in case.
Calculating the required amount of paper (X) and the number of foldings (Y) that can absorb enough kinetic energy to buffer the impact by a person weighing A kg jumping at the acceleration of B m/s^2 would make a good Ph.D. Thesis. :-)
