What useful skills can be learned in three months?

Yeah, second this. My physical therapist after my stroke recommended doing thirty pushups and thirty situps every day... which when I started would take most of the day and leave me wiped out (because, hey, stroke) and after about six months of PT became something I knocked off in the morning before going to work, but I regretted giving up the habit (and have recently picked it back up).

Where are resources for finding an effective, context-appropriate exercise routine?

Fourthing the exercise habit. A good tracker I have found to stay at it and for confidence building is Fit-o-Cracy

I would like to offer an alternative point of view: if you have 3 months to kick-start yourself, start by exercising in a very focused way, on something you don't expect to become routine: for example, if you do 3 months of lifting/strength training/high intensity interval training, you will build up enough muscles that making exercise routing when you go to college will be much easier than doing it now.

Thirding exercise habits.

approaching and interacting with hundreds of prospective mates

That's a bad idea, unless you live in a city with several hundred thousand people.

It's not a bad idea - it is something that should be applied with some consideration to context and locale. The rant on the other end of the link is possibly even more simplistic than the one specific socialisation strategy ("Mystery Method") that it opposes.

Here's my recommendation: build a web application that stores and retrieves data in a back-end database, from scratch.

In the real world, you're not given exercises to test specific skills; you're given problems you have to solve. Sometimes you will have no idea how to solve them. Sometimes you'll end up solving them badly, and you'll learn from your error. Sometimes you will have to learn a whole new skill at a rudimentary level on a very short time scale. Sometimes you will be forced to steal something someone else has done with minimal idea of how it works. The real world is ugly like that.

You are, of course, at liberty to not accept the challenge, but if you do, here are my recommended ground rules:

• You have to put the entire stack together yourself. You build the server (if you're especially hardcore, you could construct a physical server yourself, but I don't think anyone would blame you for just running a VM installation), you configure it to serve web content, you build the database, you write the web application and you test and debug it.

• No third-party built items. Wordpress is not allowed. Prefabricated web server VMs are not allowed. You are allowed to steal code snippets and config files, but you have to understand what they're doing.

• You have to pick data of moderate complexity for it to store and retrieve. Something on the scale of a music database, with artists, albums, track titles, genre, year of publishing, etc.

• You have to choose what technologies you use. If you want to run PHP on an IIS webserver, talking to a Progress database, no-one can tell you otherwise.

• You're encouraged to ask other people for help, scour web forums, and learn from other people's examples. Stack Exchange is highly recommended.

• If you have an idea for a different project of similar complexity while doing this, do that instead.

• When you're not working, enjoy yourself.

This is a common project for CS undergrads, so if you find yourself doing it now, and then doing it again in 18 months time, it will give you plenty of opportunity to observe your development.

If your goal is to found an IT startup, I'd recommend learning basic web development. I formerly used rails and, at the time I picked it up, the learning curve was about a month (just pick a highly rated book and work through). If not web, consider app development. If you know a bit of Java, Android would probably be the way to go. With either of these, you'll have a skill that allows you to single-handedly create a product.

At the same time, start keeping a list of ideas you have for startups. Some will be big, others small. But start looking for opportunities. Particularly focus on those that fit with the skills you're learning (web or app).

Potentially, that leaves you two months to start your first startup. Doesn't have to be great. Doesn't even have to be good. But knowing that you can take something from idea to product is extremely powerful. Because now, as you're learning, when you see an opportunity, you'll know how to take it.

More, it will allow you to fit your studies into your ideas. In your algorithms class, you'll see techniques and realize how those could solve problems you've had with your existing ideas or spark all new ideas. And if you don't walk out of your first AI class with a long list of new possibilities, something went seriously wrong :). But everything you're learning will have a context which will be extremely powerful.

All this time, keep creating. Any good entrepreneur goes through a training process of learning how to see opportunities and take them. You have four years of access to excellent technical resources, free labor (your peers), and no cost to failure (and learning how to handle those will be another step in your growth). If you go in with an ability to create (even a very basic ability), you will not only be able to make use of those opportunities, you'll get far more out of the process than you otherwise would.

[also: I'd like to second the recommendations to establish an exercise habit]

Motivation: Making lots of money to donate to effective charities

I love this goal!

Thanks for the links.