Research Experiences for Undergraduates. Summer research often but not always funded by the federal government, usually on the campus of a college or university (but not always), usually with a stipend and/or housing and/or travel reimbursement and/or board, lasting 6-10 weeks. About a dozen students at each site working with professors on various research projects.
Similar programs go by lots of acronyms - SURF (summer undergraduate research something), SURP, SIBS, etc.
For example, Amherst hosts one: https://www.amherst.edu/academiclife/support/funding/students/amherst-student-research-funding-opportunities/summer-research-opportunities-at-amherst/surf-program
Williams has something smaller: https://biology.williams.edu/research/summer-research/
Those are for their own students but many colleges and universities host programs open to anyone from any college.