One thing I was doing was finishing my card stock 1930's Chicago Noir set. This is for playing gangster/pulp games. It features a bunch of 3 and 4 story tenement buildings, a nice large warehouse, a diner and a speakeasy. It all goes together on a 3' x 4' base (made from a pre-made artists canvas painted dark grey).
It looks good and here are some pics:
I also made a modular set of basements and corridors (for when you need to make a sudden getaway of for moving illicit booze).