While waiting for my luggage at O'Hare, I saw a HSD sign: Think of Your Tank as Half Full Pretty clever
I saw the same one on I-5 in Fife (near Tacoma WA) it was over a Hummer Dealer! I almost lost it. I drove back 3 days later to take a picture of it and it was gone! I guess the Hummer dealer was not amused as I was.