80's Aerobics Class- Each person should dress in Brightly colored leotards or sweatpants, sweatbands and of course, the all important Leg Warmers! This is a great one for the Boss to dress as the Instructor and carry his/her whistle.
7 Deadly Sins- requires 7 members. Envy- wears all green. Sloth - dresses poorly/sloppy and is very slow moving. Wrath is dressed all in Red (paint the face as well). Pride dresses well and constantly sings his own praises. Lust
Braveheart - For this you'll need someone with a bit of talent for sewing. Create plaid kilts and sashes, paint each members face blue and carry swords and shields.
Dancing with the "Stars" - Partner up and the divide the groups in half. One side will dress as dancers with fancy dancing costumes and the other half will wear large stars (created with Bright Yellow Posterboard) and attached to their fronts and backs.
Gang Green- have all the members in your group dress all in green- sweatpants and sweatshirts work really well for this. Each person should wear a green bandanna as well. If anyone asks, you're "Gang-green"!
Geek Squad- each member dresses as nerdy as possible. Pull your pants up a bit too high, button those ironed shirts up all the way, make sure the bowtie is on, white socks and black shoes, pocket protectors and carry around a manual of some sort. (Computer manuals work great!)
Hogwarts Professors- This one is popular with Middle School teachers due to the huge interest in kids this age. Have each person in the group choose a Professor from the Harry Potter Series: Snape, Albus Dumbledore, Minerva McGonagall, Hooch, Sprout, Flitwick, even scary ol' Umbridge!
Lady Gaga's - Gone Gaga? Have each member dress as Lady Gaga- each choosing a unique outfit- anything goes with this chic- various color wigs, heck- you could dress like a piece of meat, literally!
Michael Jackson Through the Years- This costume is particularly effective for families with varying age members. Each member dresses as Michael at a particular stage in his life. When he was just a little fellow in the Jackson 5, to thriller (white glove and all) and up.
Pac Man & Ghosts- a wonderful choice for families with smaller children, the adult can dress as Pac Man & Mrs. Pac Man by wearing a large yellow circle (created out of painted cardboard) cut to look like pacman. For Mrs Pac-Man, simply attach a pink bow to her hair. Dress the remaining members of your party as ghosts using various color sheets/fabric.
Rainbow- each member dresses as a color of the rainbow, be sure to paint faces & hair the same color (if possible!).
Retired Superheroes - Create various retired superheroes including a bald superman, middle age wonder twins, chunky wonder woman, etc.
Road Kill Cleanup Crew- each member wears reflective orange vests (available at the dollar store), carry small toy shovels, bags and slightly bloodied stuffed critters.
South Park lives on- For a more mature group (or would that be Less mature??) each member could dress as a different south park character: Kenny, Cartman, Stan, Kyle, Chef, Eric, etc. Keep in mind that at some point in the evening, it's appropriate to "Kill Kenny".
Survivor Cast- This works well in warmer climates. Each member of the group dresses in rags, carrying a torch (tiki torches work well for this!) and wear bandannas for each "tribe". Be sure to create your own Tribal name!
These are a few of our favorite Group Costume Ideas, Feel free to submit yours in the comments Below!