I think the poodle skirt would be relatively easy to cut (just have to be a top fold-that is where the waistband could be)
You could do so many cute things-have the girls dress up and take pics-they can decorate frames (the wood ones that cost $1 at Mike's) and put their pics inside. You could have a fastest milkshake drinking contest (ooh-but they might get ice cream headaches! LOL)
If you go to a thrift store you can find vinyl albums and hang those from the ceiling for decorations.
Here are a ton of fun party ideas:
http://www.birthdaypartyideas.com/ht...60s_party.html
*if you don;t want to read them all-one I thought was cute was getting an Elvis poster, the kids "kiss" Elvis with lipsticked lips-like Pin the Tail on the Donkey, but giving Elvis kisses! LOL