I picked up one of those orange and white flasher barricades from a road repair site. Threw it in my trunk and drove home. At home I painted a big "Yes" on the upper support panel. My paint job was actually awesome, and I was artistic enough to incorporate an image of her theme for asking me out. She loved it and kept it in her bedroom for a week. She didn't mind that it was always flashing.
The downside is that you're basically walking off with government property. We later returned it under the cover of night.