Last year, our then 5 year old DD & 3 year old DS participated in the cookie-baking at The Land attraction in Epcot. (When you walk into the attraction, it's to the left of Sunshine Seasons & behind the "The Land" ride.)
They got cute little chef hats, baked chocolate chip cookies (full child participation), and then got to take a chocolate chip cookie w/ them.
And, it was free!
[Edited to add - This is the Jr. Chef's program that the above poster mentioned. Thanks! I couldn't remember the name!

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This year, I'm thinking about the Wonderland Tea Party.
Also, in Epcot at each World Showcase country, there are "kidcot" stops. At the 1st country (Mexico), the child receives a mask & get to color it. Then, at each country, the child stops at the "kidcot" stop & gets his mask stamped. The "kidcot" CM also attaches a little paper cut-out to the mask that is symblic and/or memorable to that country (e.g., in Germany - it was a teddy bear; in Norway, it was a Viking ship). When the child has received a stamp from every country on his/her mask, he or she receives a small, full-color poster.
You can purchase "kidcot" passports that the World Showcase CM's will sign & stamp as well. However, we already had the autograph books & I thought it would be nice to have everything in one place, so we asked the World Showcase CM's to sign our children's autograph books - which they did. And, most of them, wrote something in their country's language in addition to signing & stamping.
There's also Belle's Story Garden at MK. We didn't do this last year, because we simply ran out of time! But, it's supposed to be relatively not-as-crowded as some other attractions, and Belle brings the children up on the stage w/ her to act out the parts. Her story garden is located behind the castle, I think.
Our favorite character meal was breakfast at CRT - because of the wonderful interaction we had w/ Snow White! Absolutely pure Disney magic! Also at CRT, our DS accidentally turned his orange juice over, and he was so upset. The CM was so nice & friendly & brought him some "pixie dust" (gold confetti) to help dry his tears.
We also loved the character interaction at Liberty Tree Tavern.
And sitting up front in the monorail was a treat too. I had heard that the kids would get a certificate if we had the opportunity to ride in the front. We didn't receive any certificates, but it was quite fun just the same.