@RM Not sure if you are looking for something fun to do but I had a pack of gummy bears on my desk that had been sitting in a warm environment. The heat meant that they had started to stick together some so I picked them up and dropped them to knock a few loose.
Material hyperelasticity + viscoelasticity, temperature (and time-) dependent cohesive contact, and a dynamic drop event.
Perhaps not a holy grail problem, but not a terribly easy one and perhaps a fun way to pass a rainy day 🙂