We celebrated DS's 13th birthday at WDW...got the birthday buttons at each of the parks and DTD. When I made the ADRs I told the CM we were celebrating as well. Each time I checked in at the restaurant I said we were celebrating, but I didn't ask for anything special.
At LTT for dinner, I was asked if I wanted a cake or just a cupcake for his birthday when I checked in...opted for just the cupcake since I didn't want to carry leftover cake around MK...not sure if there would have been an additional charge either.
At LeCellier for dinner, he was given a special chocolate mousse dessert that had "Happy Birthday" written in chocolate on it and a birthday card from the CM and staff.
At Hollywood & Vine, he received a special birthday cupcake and the CM announced to the whole place it was his birthday.
At House of Blues for lunch, he was given an ice cream sundae and a HoB mardi gras bead necklace.
At 50s Primetime, he was given a special birthday cupcake and our server, cousin so&so, made the section sing Happy Birthday to him, she gave him the biggest hug (which turned him beet red, but he loved), and a birthday card that cousin so&so asked the whole section to sign for their cousin. It was great...all the strangers wrote in the card just like they were family. This was a great place to celebrate...DS's second favorite.
At WCC for dinner, he was really thirsty so our server, Raging Bull, brought him out a half gallon size mason jar drink and a custom made 6 ft. straw with it...said since he was a lazy teenager now, he (Raging Bull) knew he'd not be getting up to get that drink. They also brought him out a cute little chocolate bundt cake with whipped cream on it...told DS not to touch it till they "was done a sangin'" and then the CMs sang the most awful rendition of Happy Birthday, which DS loved. As they sang the last "Happy Birthday to you...." 4 of the CMs swooped upon his cake and ate it up in front of his eyes...it was a priceless moment! He'd been had royally!! Then they brought him another one just for him...but, one of the chow hog CMs, came back with a huge wooden spoon (the size of a boat oar) and hovered over DS then asked, "You sure you don't need any help with that?" DS laughed so hard. When we went back at Christmas (6 mos. later) and ate at WCC, DS searched the CM's faces to find Raging Bull and the one with the spoon...found the one with the spoon and said hi...asked him if he still had the spoon. The CM, whose name is Paul, went in the kitchen and came back with the spoon...DS sat through the entire meal with it by his side...quite proud too. When we finished he walked over to Paul and gave it back...told him he might need it again the next trip. This was by far DS's favorite place to celebrate his birthday.
That is all I can remember for DS's birthday...although on his first trip to WDW, which was to celebrate his 7th birthday, upon check-in at the Poly, the CM noticed he was tired (we'd been driving from Valdosta, GA) and tried to perk him up by saying "you're at WDW", to which I added "he should be happy, this is is birthday trip". She asked if it was his birthday, and I said not today, but this trip was his gift. She said very quietly, we can take care of this. Well, later that afternoon when we returned to the room there was a cake, balloons, party hats and horns, a birthday card signed by Mickey and the gang, and a birthday CM button for DS. I though that was about the nicest thing...it was courtesy of WDW.
I guess the main thing is that you can request birthday cakes for many places at WDW, but most need to be done in advance. If you want to embarrass the heck out of him, then you might want to make a point of telling the CM who actually does the serving at the restaurant...the podium alone isn't enough we found out...Biergarten didn't do a thing after I told them at the podium. I went with the idea, that if anything special was done then that was great...DS really didn't want a lot of attention for his birthday...he didn't even want to have a party at home, but did agree to let us celebrate on the trip...Mom's need to celebrate the only child's special day was understood...lol
If you do a search you should find a thread on how to celebrate your birthday at WDW...it's pretty full of info.