A plant question and a present

My daughter, Wendy, brought over a back to school present the other night. Lots of fun things I can use at school!

I might have to keep the pens at home...sort of need them here! 

I have everything about ready to open the library next week. I always start off by having each class come down individually to talk to them about expectations, where things are, & how to look books up on the computer search. They will each get to check out a book as well. After this, the students come down on their own when they need a new book...only the First graders, Kindergarten and Preschool come for a storytime every week. 

 One of the ladies brought this plant specimen to class the other night. She has a tree that these grow on and wanted to know if anyone knew what they were.

They aren't crab apples, and they don't get any bigger than this. She moved to a new house last fall and is curious to find out what it is. She said even the squirrels wouldn't eat them, though one of the ladies in class tasted it. It didn't really have a distinctive smell, or at least one that I was familiar with. 

 
 Any ideas what it is?