I like to use #OpenSource tools when I'm teaching, and I'm teaching more game programming to kids age 10-16 in the summer. Love2D worked really well, though I'd like to help them also learn how to make game art.
I mostly just know #GNUimageManipulationProgram but I'm not giving children flash drives with a program named "gimp" on it. Can you imagine what their parents would think??