Lego Man Costume - Halloween Costume Contest via China Falk Works. 2 cardboard boxes for the head and body, glossy spray paint, and disposable paper bowls on the body and head. Paint on the face and cut out the mouth.
Lego Theme - A Lego construction party. I love the idea of supplying a little bit of fancy dress to each mini guests, rather than asking for full fancy dress. That way parents who can't afford it won't have to turn down the invite.
These Lego masks use a cardboard frame wrapped in yellow papers, and they also have translucent eye-holes, so you don't have to worry about bumping into things. They are very light but also very sturdy and impact resistant - perfect for a party!