Make-your-own costumes...what comes to mind?  Sewing, elaborate, taking lots of time?  It doesn't always have to be that way, right?! 

Many costumes can start with a sweatshirt or a box.  My favorite costume was in 4th grade; I was a pair of dice with my friend Kerry.  She and I painted the boxes, pasted on paper dots, and wore tights and a turtleneck.

Some DIY costume links:

A Seattle Times article, that links to FamilyFun and parents.com, so we might as well too!  FamilyFun also has creepy cuisine

A Baltimore Sun article with lots of links

About.com has costumes and family crafts too
 

HGTV has 3 minute video clips that include no-sew costumes and toddler costumes

Some DIY costume books for kids and adults: