learn to program before the summer then write an app, fix some old enterprise programs, etc
some folks make 10K in one month, work two, then travel for two.
read a lot of books before the summer then write something unusual - get 10K for the advance.
really, really learn about stock trading. skip the tips you hear from here, there, and on blogs.
you can start with $100, leverage the trades, etc. study the most volatile stocks before the
summer, ones that trade up and down cyclically and time your trades. 10K in 4 months is
reasonable.
if you started with a little cash, flip not audio but specialty cars. buy convertibles in California
and sell them in the Midwest. two times if you're really good, maybe 4 if you're starting out.