This may be more formal than what you'd like, but you could try
Coursera, which partners with topflight universities (UPenn, UMich, Princeton, Stanford, etc.) to offer a bunch college-level courses free online.
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Team 2337 | 2009-2012 | Student
Team 3322 | 2014-Present | College Student
“Be excellent in everything you do and the results will just happen.”
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