The sleepy summer streets of college towns are beginning to clog with out-of-state license plates. The local Target looks like it has been ransacked by a flash mob. Plastic funnels (a.k.a. beer bongs) are out of stock at the Dollar Store. You know what that means: College is in session!

Across America young people are descending on this nation's fine educational institutions on the path to responsible adulthood and a decent internship -- or perhaps just in hopes of meeting someone really hot. Besides the courses outlined on the syllabus, these students of life will be taught some less formal but equally important money lessons during their four-plus years on campus.

Perhaps it has been a few years (or decades) since you strolled your college campus. Maybe you are dropping off your young one at his first dorm. Or you could be a wide-eyed freshman who happened upon this article. It doesn't matter, because you don't need a student ID to get something out of the lessons below. Here's the stuff you learn in college, even when you're not really paying attention:

Lesson No. 1: Trying to make up for lost time by cramming doesn't work. No, not even with six cups of coffee in you at 4 a.m., looking at the material for the first time. There's no substitute for keeping up with the reading from the beginning, if you really want to learn it. So, too, with investing for your retirement: You can't cram all your savings in at the last moment. (Just look at the example of Patrice and Bianca in our Investing Basics area.) Start early and develop good saving habits. And thank your lucky stars that your 401(k) paperwork is multiple choice.

Lesson No. 2: You get just as much credit for passing the easiest courses, and you get to sleep later. Whether it's TV in Our Society: The History of Soap Operas or Modern Clothing Theory, there are some awfully easy courses that don't require a whole lot of effort to keep up with. So, too, in investing. Some of the best investments are what we call "Obviously Great Investments." Investments like Coca-Cola (NYSE:KO), the Gap (NYSE:GPS), and Microsoft (NASDAQ:MSFT). Heck, go ahead and use the investor's version of Cliffs Notes and go with an index mutual fund. You don't have to find companies that you'll never understand in order to invest well.

Lesson No. 3: Marry the one with the good personality, not the really, really hot one. How much time do you spend daydreaming about the best-looking guy or gal in your class? If you're even remotely normal, the answer is "a lot." But it's usually not the hotties who will bring you a lifetime of happiness. So, too, with stocks: The hot highflier is not too likely to reward your long-term faithfulness.

Lesson No. 4: A little self-discipline goes a long way. Get ready to experience the "freshman 15," that extra 15 pounds of weight that mysteriously attaches itself to you while you're too busy having fun to notice. In life, credit card debt somehow, mysteriously, manages to do the same thing if you're not looking. Trust us, $45,000 in extra debt baggage is not attractive. For either of these problems, the lesson is that it's easier to acquire the weight than it is to burn it off. But it's not impossible.

Extra Credit: Mooch off Mom and Dad for as long as possible. You're young. You've still got your hair. And you aren't yet used to adult furniture and having a cleaning lady. Stay youthful as long as possible by shunning the trappings of adulthood -- new cars, expensive digs, martini happy hours. (OK, you can still do the happy hour, but go for the dollar beers at the local pub.) Right after you graduate you get a bit of leeway from society. If you can keep costs down by shacking up with Mom and Dad for a while, do it. But don't be surprised to find the "Dear Son: Please Move Out" letter on your pillow after a few months.

Dayana Yochim spent four months under her parents' roof "transitioning" to the working world after college. She owns none of the companies mentioned in this article. The Fool has a disclosure policy that many parents may wish to modify for their live-at-home adults.