Bottle cap tripod
Overheard: "That would be a fun shot. Too bad I didn't bring my tripod."
"Oh, you need a tripod? I have one right here. Do you have a water bottle?"
Seriously. A little piece of plastic that retails for $10 at CharlesAndMarie.com. You snap it on top of a water bottle (which let's face it, we are still carrying when we travel) and voila! Instant tripod. So kewl!!!