Yes, that’s a chair on top.
I’ve seen this van parked around my neighborhood for several months now. It’s always COMPLETELY AND UTTERLY PACKED WITH JUNK. The interesting thing is that the junk changes from time to time. Sometimes the cardboard in the window changes, sometimes the stuff on top changes, and due to “alternate side of the street parking” (Wikipedia article for those not familiar with the concept, and Jen Bekman has a nice little write-up of her experiences) it’s moved around, although judging from the junk in the driver’s seat, I have no idea how.
A quick inventory of what can be identified through the front window includes several CDs, a light bulb, a cable box remote, markers and pens, receipts, rolls or receipt paper that you might put in a calculator or cash register, third-class mail, sunglasses or swimming goggles, and a flashlight or a dildo (I’m not too familiar with either of those), plus a big piece of cardboard designed to keep the sun out, or, more likely, prying eyes away.
On top are several suitcases, a chair, a lamp, a wire storage thing that you might use in the bathroom or hang on the back of a closet door, a spray can of some kind, and a shopping cart. Most of it covered with a tarp.
The weird thing is that there is a Manhattan Mini Storage facility about four blocks away.

It’s tough to see the junk in the window due to reflections, but trust me, it’s filled with stuff.

What would you need with a cardboard sun screen in winter time?
Ever thought of tossing a loud clock on the roof and see what the bomb squad makes of the thing?
Actually, I kind of feel sorry for whoever the van belongs to since it looks like they strapped all their worldly posessions to it and might be living in it… Either that or they have some sort of psychological problem to be hoarding all that stuff in such dangerous disarray. That person needs help one way or another.
Josh, is the van still around?
I moved a while back, and haven’t really been back to that neighborhood to see if the van was still around.