sand or dirt to the eyes is always the best improvised weapon.
also the old soap in the sock, or a combo lock works well too.
also the rolling disc of say like a pizza cutter, or a electric saw blade tied on a rope strong string or chain is a highly effective long range weapon.
as for projectiles use the tube of a ball point pen remove backing, ink holder and tip so its just a plastic tube. and with two rubberbands and a mechanical pencil you have a pretty strong dark gun. actually punctured my friends skin back in high school not believing there was any real "power behind the punch."
PM me if you have any questions.
i prefer the combo lock in the sock though. ( not just because it rhymes either)
"In order to take life, you must respect and understand life."
-Miyamoto Musashi (japanese swordsmen)