Just curious because that's the only name brand thing I've seen on the show, and it seems like everyone wears them at some point (Jack a lot, Janet often, Larry sometimes, even guests like the little boy Billy). Actually, now that i've gotten the DVDs, it seems like in the early seasons Jack was wearing regular knock off type shoes, and then around season 4, once the show had gotten very popular, him and everyone else started to always wear Nikes.