We've done the birthday celebration at Plaza Inn twice and loved it both times!
The first time was for my birthday! I was only 1 of 2 adults celebrating with all the kiddos, but we had a blast! It was $10 then, not sure how much it is now, and we got to decorate a cake! Yes, it's silly, but it was a lot of fun! You do a conga line with Mickey and Minnie and get to take a pic with them!
The second time was for my nieces birthday and she loved it too!
I say it's totally worth the $10!