I also posted this camp opportunity in another thread, but thought the topic, in general, merited its own thread:
http://ai.stanford.edu/sailors/
Next year for my daughter! Son would love it, but this one is only for rising sophomore GIRLS. First year, completely free and underwritten by silicon valley tech companies. Part of the women in math and engineering initiative, no doubt 
What else is out there?!?
http://www.thecollegiateblog.org/2013/12/12/80-free-summer-programs-for-high-school-students/
Ha ha, maybe this amazing list eliminates the need for this thread.
Thanks for sharing the list. Finding things for rising sophomores to do seems to be a challenge. I’m not limiting the search to science - trying to cast a wide net.
DS participated in a STARTALK program last year for Mandarin - three weeks at a local university. Free and earned college credit. They were also offering Arabic. It’s a neat program for those interested in languages, if there’s one in your area.
@fullofbs --this is amazing! Thank you for posting. Also wonderful that you son earned college credit–a win, win, win!
DS is thinking of doing local youth corps at home. It’s competitive and hard manual work for 6 weeks, but he will earn over $1500. He will also look for jobs that take 14 year olds.
I hadn’t even thought of this option, thanks for posting @payn4ward. Awesome suggestion.
@itcannotbetrue: Choate used to host a StarTalk Mandarin program, but no longer. Now only at a HS about 40 minutes north. My two DDs did it for several years. The DD you know was planning on taking classes at BS this summer so she could fit in another language next year. AND a rowing camp in August.
@itcannotbetrue thanks for posting about Stanford. I just checked it out and seems to be for “underrepresented populations, with an emphasis on diversity.” Works for my DD, but not for everyone who is on this board…
DD will be busy, @mexusa! As for the artificial intelligence project for girls at Stanford, that is part of a national initiative underwritten by Silicon Valley tech companies. Yes, under-represented, but my impression is that ALL girls are under-represented in math and science fields. No specifics on minority status that I saw, but then again since my daughter is too young I did not read all the fine print.
@itcannotbetrue is correct.
Just researched the youth conservation corp idea. Sadly, the local youth conservation corps in our area is limited to “out-of-school at-risk teens.” Weirdly, they even have a high school structured around it.
Thanks for sharing the summer list @itcannotbetrue.
U.S. Naval Academy has STEM program that is $550 for the week. Not necessarily cheap but not the $2500 I’ve seen for many programs I’m looking at for rising senior.
Different dates for rising 9th, 10th, or 11th. http://www.usna.edu/Admissions/Programs/STEM/
@Sportsman88 --we just applied for the STEM USNA program, funny you should mention it!
Great! Unfortunately, the dates don’t work for our daughter. USNA schedule is driven by the start of Plebe Summer and our daughter’s school isn’t out in time. Bummed.
For online learning, edX looks amazing. These are free online classes (MOOCS) offered through major universities:
You can request a verification certificate, and some of them are “for credit” 
^ That’s a great resource! Thanks for sharing.
For anyone in the Boston area, check out GEMS at Natick Labs. If I’m not mistaken, it’s also held at other army bases around the country. We might be too old for it; I don’t know. It’s a short science day camp with a stipend.
Natick Labs is for rising 5-8th graders. Some of the other ones are for HS students.