These make wonderful paper weights and could be great dad gifts!  We made these as a part of our insect unit.

Mexican Pebble Rocks make the best bugs! I found some of these wonderful stones at a landscape supplier. They are a nice size (palm size.)
rock-insects
I had the children begin by drawing their design in sharpie.  This is important for the painting step.

rocks-insects-1
I had the children paint their rocks with acrylic paints.

rocks-insects-2
We let the acrylic dry.  You can see the sharpie underneath the paint!

rocks-insects-3

The details were added with paint pens.  So cute!
rocks-insects-4
rocks-insects-5