I, uh, went for a walk today, and...
...figured I better start thinking about bases! Basemaking isn't my strong point, so I'm not even really sure what I'm looking for, but these were a cool find:
My town flooded over the summer, and this lumpy, plaster-like stuff is apparently the dried river-mud that that parks folks had to scrape off the sidewalks once the water retreated.
Now I just have to figure out what the heckaroo to do with it all.