Apparently, this is normal for city basements. I'm lucky that it is just storm water (and mud) and not sewage or anything and nothing too valuable was damaged. I'll have to throw out some magazines and my area rug. I'll have to do a bunch of laundry (now that my once 'clean' clothes are sopping wet). Worst of all, I have to clean up the mud. Yuck. I hate cleaning.
And (miraculously) my ancient television still works, despite spending the weekend sitting on a water soaked rug.