Here are some of the things I use in the Strings Unit with the 2nd graders.
These cards can be used different ways. When you play - or name - one of the string instruments, they can hold up which instrument they hear. Students could match the names of the strings with the pictures.
One of the things I do is play Dueling Banjos.
I don't use the fun sheets very often - only if there's a substitute or if I need to catch a class up to another class because of an assembly or something.