a new box will cost $30 plus your labor...if you already have the tools, which any man would. are you a man? =P
.75" MDF
bag of drywall screws
caulk
something to cut straight lines in the wood- table or circular saw
something to cut the speaker hole- jigsaw
something to put the wood together-drill
specs for box-
www.rockfordfosgate.com
specs for the size of box- your math skills.