L.C.
First of all let me say, I'm jealous! All we've been getting for the past 3 years (she's almost 5 now) are princesses and fairies.
Some ideas - I don't know if you can find them this time of year but you can get those little half masks and do some kind of craft where kids can put stickers on them and color them (glue and paint if you're feeling adventurous).
Or you can get some books and have the kids make superhero paper bag puppets then (if their attention span lasts) you can have them put on a puppet show. I guess it depends on the age group, if they're all on the younger side crafts might be hard.
You a have super hero dance party. Where you play music and get the kids to "fly around".
You could "try" to have a "pin the mask on Superman" game, even if you did it w/o blindfolds, kids might like it.
That's all I've got, we're going through this right now for the 5 year old party...but it's Tinkerbell LOL.