About This Particular Macintosh (ATPM) has a review of a rather interesting item – the Portectorz line.
What are Portectorz you might ask? Quite simply, they are port covers for the 12-inch Apple iBook and 12-inch DVI/Aluminum PowerBook. The covers are made out of silicone, and they mount on the iBook or PowerBook through pressure, and they serve to keep dust, etc., from enterering your ports (say you were going to be placing the iBook or PowerBook in a container not made for a PowerBook or iBook where you might have dust, hair, etc. inside) – ATPM doesn’t recommend running either one with the port covers in place, because of heat buildup and dissipation.