credit over summer

<p>Im currently a sophomore and I am trying to decide what to do over the summer. I definitely want to earn some kind of credit, but im pretty busy over the summer so I dont want to go to anything over 3 weeks long, I also want to keep the cost under $3000. Id love to go to a residential camp but im open to online. Also im interested in computer science, math, biology,etc. Any suggestions?</p>