Homer Simpson on the front.....going...Doh! as a rock hits him in the noggin.
Bart on the back holding a sling, laughing.....with the thought bubble:
"Thanks Slinging.Org!"
Or maybe the 'Scales of Justice lady' blindfolded......made to hold a sling instead of scales.....
The caption:
"4 out of 5 hot, blind, and fair minded statues can't stay away from Slinging.org!"
lol.
Actually, I really like the slinging dude incorporated into the letter G.....maybe make him setting up for an overhander and it would be perfect!
Peace,
TS