Thrifty is a broad topic, so you'll have to indulge me. I know this isn't what you'd expect for a Thrifty Thursday post, but I didn't want to put it on a Make-It Monday (it's too simple). But this is a lesson in using what you have, or recycling/re-purposing.
So, Bottle Bowling is just that, bowling with bottles. It can be any kind of bottles. 2L pop bottles, any size water bottles, baby bottles, etc. Collect 10 used bottles, remove any labels, and fill with water or sand. We like using water and tinting it with food coloring to match the season or holiday (pictures came from Halloween, hence the orange).
Grab a ball, any ball, be it playground ball or soccer ball or even a softball.
Set up your water bottle "pins" and have at it. Kids tend to make up their own rules to a game as they go, or you can teach them bowling specifics. Have fun, and use what you have.