Update #2: My picture and a response can be found at What's That Bug? Scroll down a couple of pictures and you will see my picture and their explanation.
While photographing leaves Tuesday I found this odd but beautiful site. I am assuming it is an egg of some sort. The picture does it no justice the colors were gorgeous! I think we will have to check out my friend's favorite site What's that Bug. G was trying to catch minnows when I found this so he only saw the pictures... he (and I) are very excited to check on it's progress when we go back to the park next week.
UPDATE: My good friend School for Us emailed me today with some links that may identify this beautiful mass... a gall aka wasp house. Some wasp larvae secrete a chemical which mutates the cells of the young leaf or branch and causes it to form a gall which provides food and shelter for the growing wasp. Wow! Check out these links for a better explaination and a beautiful poster.
Apples on an Oak? by Walking Prescott
Oak Galls by Handbook of Nature
Wasp Gall Poster By Ron Russo