We'd say costumes are a must for a superhero party -- what's the fun, otherwise? No kid wants to be in street clothes when he could be running around, wreaking havoc in a cape and mask. But how about encouraging your guests to get a little more creative than store-bought Superman and Batgirl outfits? Have the kids come up with their own superhero costumes, and you could have a "naming ceremony" once everyone's arrived. Siblings and friends could even come in pairs with sidekicks -- or nemeses. But if you feel like that's adding too much pressure and prep time for your guests (and their parents), bill the event as a "create a superhero" party and have the kids transform themselves at the party from little Clark Kents and Lois Lanes into mini caped crusaders.
Check out the next page for superhero-creation ideas.