Hi,

I have the typical square ceiling central a/c vents in my house.
This style:
http://www.thisoldhouse.com/toh/imag...entralair4.jpg

I close them in the winter of course, but yesterday noticed that they
are definitely still drafty. Besides those magnetic vent covers, which
I'm not sure will even fit or stick, is there a better way of
insulating these? I haven't seen any products out there at all, and am
thinking about just making something up if I can't find anything
decent. Any suggestions?

Thanks!

--Jim