With colleges and universities, one way is to identify who has what federal research grants. Federal research grants nominally in general have some kind of outreach or broadening participation requirement. Involving HS students is one way to get that done. And if the students and the teacher are willing and the project suitable maybe some good science results can come out of it.
You can find out who has NIH grants at http://projectreporter.nih.gov/reporter.cfm
The NSF site is down now but it is nsf.gov/awards or something like that.