https://www.non-trivial.org/
The marketing smells very scammy, but I can't figure out their angle.
It claims on be totally free, and even awards scholarship money for student research projects.
But the website and emails are very high-pressure, all about improving college applications, like a college consulting company, which seems very strange for a charity that allegedly is trying to help people. High school "research" is known to be a gimmick, so what are they up to? Why would they pay untrained children to do research?