Both my boys (11 and 15) like things that they can "play" with. I don't know if it's possible for you crafty folk to personalize things like yo-yo's, balls, tech decks etc... If they can toss it, throw it or otherwise make it go, it's probably a good idea.
The teen especially, consumes an alarming amount of food

so perhaps some type of candy.
My 11 year old collects key chains and the teen did as well when he was a little younger.
Most kids this age are obsessed in some way with technology and would probably like a mouse pad, cell phone charm etc...
Any school type of supply would work as well such as pens, notepads, rulers etc...
Honestly, boys are usually not too picky and unless it had a girly theme, you'd probably be safe with most of things we've seen on this thread. As far as characters go:
The 11 year old loves Nemo, Simba, Donald
The 13 year old likes Stitch and Donald
Goofy and Pluto would be good choices as well as would Mickey