Here are some variations on the idea of combining the G with a smiley face (=
Left one is using a particular font with nice serifs. Middle one uses a modified G from the Harry Potter font. Right one is a custom designed sans-serif G.
I want you to notice how each one is designed to resemble a G on face value (no pun intended), but also upon further inspection the smiley face grin is embedded within the symbol. The symbol also fits as a currency symbol.
