Congrats!
My hubby proposed in a traffic jam. We were on our way to my dad's b-day dinner, actually, but my hubby had just picked up the ring that day and I guess he was impatient. Out of nowhere, he just sort of threw the ring box at me and said, "I can't wait anymore! Will you marry me?" It doesn't sound romantic, I know, but the whole idea of him being so excited and happy that he couldn't wait another second was, well, very endearing. You might do something like that. Of course, I'm not sure it would work as well if the "I-can't-wait-another-second" thing was feigned.