Collections?

My son has to start a collection of something for is bs project.  I have NO idea what in the world the boy wants to collect.  He likes football and baseball cards.  He found a bunch of rocks to take but I just don't know.  I never collected anything but arrow heads as a young child.  And I didn't keep them.  :(  So, we went out in the driveway and found all types of rocks.  They were different shapes, colors, sizes, textures and some even had fossils in them.  It was pretty cool. 

What did you collect as a child?  What did your brother, sister, spouse or parent collect?  There are so many things.  I am just curious.  Please.  Share.  :) 

Blessings,