Spiderwort- or Tradescantia ;-)
CMK

That's it! Thank you!

I'm with your parents and would like to eliminate them as well due to their sloppy habit of falling over but chances are you'll find them cropping up in other spots--they do seed around. Check them out on Google if you're interested in more information. As christinmk mentioned, Tradescantia is the botanical name; the common name is spiderwort. While they do attract pollinators, they're not my favorite perennial thanks to their floppy habit.

They are pretty sad looking. At my house I have lots of areas bordering the woods that I want to landscape with wildflowers and natural plants. I think they'll work out well there. In exchange, I gave my parents the iris tubers that were also ID'd on this forum. Love a good trade :)