I participated in a competition in middle school to see who could formulate jello that would stay up the longest when nailed to a wall. The one rule was that your jello could only contain ingredients that normally show up in jello. The deciding factor turned out to be not what the jello contained but how it was hammered. If the jello ended up flush to the wall then it would stick, eventually harden, and stay there indefinitely.

On the other hand, I took a more unique approach: I pointed out that fruit was an ingredient that commonly shows up in jellos. So I nailed my jello to the wall through a ring of apple and relied on that to hold it up.