Bonded Dacron(http://www.foambymail.com/DACRON/polyester-fiberfill.html)(http://www.ebay.com/itm/27-Wide-Bonded-Dacron-Batting-SOLD-PER-YARD-/390104452113?pt=LH_DefaultDomain_0&hash=item5ad4098c11)works great for damping ports. You can roll it as tightly or loosely as you desire, which will enable you to tune the port to your taste. The stuff is available at most fabric shops.
Subwoofer Plug
Howdy, how to do you get or make a good subwoofer plug? I have a pair of SVS subs that I'd like to plug and, given that I'm trying to blend subs with Maggies, any sub I get in the future will either be sealed or I would like the option to at least trying a port plug. Problem is that unless it comes with one I have zero idea what to do. I suppose I could throw my dirty laundry in there, but that doesn't seem optimal somehow..... I should probably stick to clean clothes. ;)