You might also want to check Stumps or Shindigz, Retrojunction and Anderson Events. I have done several "decade" themed events and these websites have been very helpful. Some of the larger items are expensive, but if you know someone who can replicate the item or if you plan to use the items again in the future, it doesn't seem so bad.
We have officailly decided on a GROOVY theme. Beisdes the basic games we're going to be making groovy pictures where the kids can dress up in hippie clothes and we'll also have a best dressed hippie contest. Any other ideas for my theme?
I responded to another post on a Beach Party idea, so check out that post for more info. I have found www.birthdaypartyideas.com
is a usefull site. Go out there under kids parties and then they have 50 and 60"s parties. I checked it out and you might find a couple of usefull ideas.