We have all studied in high school about a small sphere falling through air due to gravity, and reaching a terminal velocity due to Stokes drag. Is there anything much more dramatic happening in a dust storm, a snow avalanche, raindrops falling through the air or marine snow in the ocean? Is everything understood? I'll answer this with a ‘no’ and explain some open questions. I'll talk in particular about our recent work on Basset history and on caustics (I'll explain what these are as well). I hope to convey the excitement in these questions, and to enthuse more people to work in this broad area.