Brother-sister halloween costume ideas?

Bambam and Pebbles and Dino
Scooby Doo characters (Thelma, Shaggy and the white sweater guy)
Three blind mice
Cards – that would be easy to pack. But you would have to make them white towels and felt (queen of hearts, ace of spades, king of diamonds) and ribbon to sew them together. I did this once with friends.

The Lollipop Kids from Wizard of Oz. Easy to do. Not much needed for props.

Peter Pan and Tinkerbell and Wendy

the Fruit of the Loom fruit. Again, fairly easy (balloons for grapes. Cut out for the banana and apple)

Two pigs in a blanket. Just buy the pig noses and wrap a blanket around yourselves. If you could figure out a way for the boyfriend to be mustard or ketchup that would be really funny! (or they could be the two pigs and you could be the mustard.)

Or, adding to Judi’s answer, maybe the boyfriend could be a fork. Heh. :)

Hansel and Gretal

ohohoh or Jack and Jill

The Three Stooges

Manny, Moe & Jack
(The Pep Boys)

bacon-lettuce-tomato

britney spear’s in a high school
bald britney
good girl britney

That’s all i got. I’ll think about it.
btw; best costume I ever saw was a guy dressed as a Rely tampon during the big toxic shock scare.

mccain and palin. it would be really scary if they were elected.

Pregnant Britney and K-fed, and maybe you dress up like little pregnant sister, (I know you’re a guy that’s why it would be funny.)

@Judi Betcha Britney and Pallin will be popular this year! Pallin in her beauty pageant swimsuit…lol

Charlie Brown and Sally
Ross and Rachel
Karen and Richard Carpenter

Palin, her husband and Bristol!

I can see Palin passing a baby doll around like it were a hockey puck!

Raggedy Anne and Andy!

If you choose Mtl_Zack’s idea, her boyfriend could go as Phil Gramm (also very scary).

Peter, Paul, and Mary

ZZ Top!

Rush!

Los Lonely Boys

Dorothy, the Scarecrow, and the Tinman.

Here are some trios:

Groucho, Harpo, Chico
Chrissy Snow, Jack Tripper, and Janet Wood
George, Jerry and Elaine
Greg, Peter, and Bobby or Marcia, Jan and Cindy