If you're reading a post entitled "Last Minute Halloween Costume Ideas" on October 31, I'm going to assume that you do not have the time to sew up Montaigne court garb, but that you can make a run to the craft store or similar. I also assume I'm not the only one geeky enough to have thrown/attended RPG-themed Halloween parties where people will "get it", because you really don't want to find yourself explaining that no, you're not a zombie, you're a waisen, if you want to have any chance at all of her going home with you.
From your closet: White blouse, long black skirt, black vest or jacket
From your jewelry box: Classy black and whites (pearls, crystal, onyx); silver; cameos
From the craft store: Cheap headband, 2 yards of black tulle, Halloween spider ornament
Bonus points: Tarot deck, wearing spider on head
Sew center of length of tulle to headband. Tack spider onto sleeve of blouse or jacket, or where you like.
From your closet: White long-sleeved shirt, dark trousers, wide belt, nice boots if you got 'em or dress shoes, gloves
From the craft store: About a yard of wide lace
Bonus points: White wig from costume store, military-style dress jacket, red makeup
Tack on lace at cuffs. Take the rest, run a thread down the center of it and scrunch it up a little; tack down onto the front of the shirt. Paint your hands red or just wear gloves.
From your closet: Black shirt, black pants, black shoes
From the costume store: Cat ears and tail, black pencil for painting on nose, whiskers, etc
You see where I'm going with this, right? If you don't have green eyes, you could wear green eyeshadow. But it's admittedly not the same.
You can wear almost anything (or sometimes almost nothing) and look like a pirate if you remember the most important pirate accessories:
1) Headgear, whether it's a bandanna, a sock hat, or an awesome hat
2) A wide sash for a belt (usually red or black)
3) A gold hoop earring
4) An eyepatch or a parrot or other novelty pirate accessory of your choice (hook hand, saber, etc)
Knight of the Rose and Cross
From your closet: Plain shirt, plain pants, belt
From the craft store: About 8' of pale blue fabric, red and brown markers
Bonus: Foofy hat, eyes that burn with the fire of inner vision
Cut the length of fabric down so it's about the width of your shoulders (use another shirt to measure). Cut a hole in the middle for your head. Draw a cross on the front with the brown marker, and draw roses with the red marker. (Marker will probably bleed through so be careful what you're drawing on.) Pro tip: belt down the back of the tabard but not the front (unless it gets really annoying)
From your closet: Loud clothes - bright stripes, bright solids especially. If the shirt and pants/skirt clash, it's probably better.
From your (or a female friend/SO's) jewelry box: Gaudy gold jewelry. LOTS. Especially earrings, rings and bracelets.
From your closet, craft store or costume store: Scarves (or cheap filmy material cut into a square). Men, wear as belts; women tie in a triangle at waist. Either, wear as headgear.
From your closet: Old raggy, dirty clothes
From the costume store, drug store or makeup cache: Something to darken around your eyes, pale down your skin and muss your hair. Look for the zombie makeup kits if you're not sure you can do it with baby powder and dark eyeshadow.
Bonus: Shuffle aimlessly around your party venue all night