So I am not sure from your post if you are looking for things that are free or just exciting extras so I will separate them
Free
Jack Sparrow's Pirate Tutorial (right outside of POTC) My nephew is STILL talking about this
Jedi Training is still a thing and you still have to get there early
Pulling the sword out of the stone (A disney classic)
Sorcerers of the Magic Kingdom (as someone already mentioned)
You can drive the River Boat if you ask (I read this in an article I have not tried it myself so YMMV)
If you sit in the first car of the train at Animal Kingdom and the conductor is in there they will let you sound the "all aboard" if you ask
It changes often but sometimes they have chainsaw contests in Canada in the world showcase which is enjoyed by boys of all ages
Little cost/sometime lotta cost
Make your own lightsaber at HS HUGE hit (if you are looking for something a bit more cost effective you can build your own Droid)
Make your own Mini Figures at the
Lego Store in Disney Springs
The Pirate's League Pirate Makeover
One of the dessert parties or cruises (we are doing the pirates and pals one for the first time in December)
Make your own Mr. Potato Head at Once Upon a Toy in Disney Springs
Design your own Magic band/phone covers in several locations
Pick a Pearl in Japan, have each boy pick a pearl and then have them turned into a pair of earrings for you (they get the fun experience you get a souvenir)
Have their silhouette done on mainstreet