My son wanted a pirate theme for his 6th birthday. We went all out for this party.  We cut out pirate swords from thin plywood (cardboard will work too) and painted them with a black handle & silver blade. We pasted "jewels" on the handles.  We sewed some eye patches and "head kerchiefs" for each child. My mother sewed together goodie bags from brown fabric and used twine as a pull close handles. Face paint was used for mustaches and beards (or stubble). We purchased Mardi Gras beads and foil covered gum coins(oriental trading) and other goodies for the goodie bags. Glass marbles served as "jewels".  Entertainment:  make your own jewel necklace (using string & sparkly beads), create your own pirate flag, pin the treasure chest on the X mark (using a "map" drawn by my son and his father), and a treasure chest shaped pinata.  Our cake was made with an idea from birthday express in the shape of a treasure chest - the kids LOVED it. My only regret was that there was snow on the ground - we had planned a treasure hunt outside with hidden gifts wrapped in different paper (each child was to have been given a different piece of matching paper to match up to the hidden gifts (so everyone got a prize.) Decorations included black & gold balloons & streamers, skull & crossbones pennants & flags, and pirate themed tableware.