Are you going to change the world? (Really?)

Rather than suggest a particular activity, I would say broaden your world view (this, typically, is one thing where being white and born in the US usually puts you at a disadvantage).

Most societies develop norms that people take for granted. In a sense, the norms aren't! They only apply to that society and like minded ones.

There are lots of social problems in the US. Homelessness, hunger, obesity, medical issues, prison population (highest per capita, I believe), etc. Many Americans take a number of these issues as granted: It is assumed that a given society will always have these problems, and that they can't be solved.

Simply. Not. True!

These problems are almost always a byproduct of the values of the society. To solve them, one needs to adjust those values, preferably without compromising others of equal or greater importance. And it's hard to realize which values need to be adjusted if one only looks at one data point (i.e. the US society)!

Go out there. Travel. Try really hard to understand other societies that are very different from the US. Don't limit it to simply observations. Understand their concept of human relations and note down the similarities and differences to those here.

THEN try to address the problems you see here. Trying to solve them without doing the above is many times harder: You'll be trying to use a bad framework to solve problems (it'll be a bad framework because likely that's the framework that created the problems).

(This is not, BTW, to say that everything is wrong about the US, but likely if there are problems here, it is a result of the culture).

I hate to put some controversy here, but it does sadden me that this country has become so used to engaging in wars and conflict over the decades that average Americans I encounter are fairly apathetic to the violence that the US engenders elsewhere. It's just taken for granted.

If you travel elsewhere (depends on where, though), you'll find that people don't take violent deaths so cavalierly.

This is just an illustration of my point. Grow up in the US and you may end up becoming a very empathetic person who's always anti-war, but you have the cards stacked against you. You need to reflect on other frameworks of thought before you can decide overall what your values should be.

I grew up in Saudi Arabia. A very repressive society. Yet I am 6-7 times more likely to be imprisoned in the US than I was there. Really think about these points!

Yeah, you could go to medical school and "make a difference". However, I'm going to guess (perhaps wrongly) you're not going to go into it for the shear pleasure of medical research, but rather, because you simply want to "help people".

You "want" a lot of things, day to day. Food, shelter, entertainment - the works. But you are not a farmer, nor a construction worker, nor a writer. Instead, you simply do whatever it is that gives you a reasonable tradeoff between marketability and enjoyment. You specialize. You become a programmer and make money (looky there, a lot of it!). Now you can use this money to pay others to full-fill your needs, and the people who receive your money are in turn specialists in their own field, and they can do a FAR better job at providing [food|shelter|entertainment] then you ever will.

The desire to "help people" is no different. You have a desire, and you have an ability to make money. Other people have the ability to satisfy your desire, for money. Pay them to make it happen.

If you go to medical school, you will spend ~$200,000 on it, and more importantly you will forgo MILLIONS of dollars during the time you are studying instead of doing what you're good at (startups, programming, investing, whatever). A million dollars can provide scholarships for 5 bright and promising students who each have a much higher chance of coming up with something that will "change the world" then you do. It's simply a question of efficiency.

Having said that, you do get to be involved at least to some extent. As consumers, we pay others to do the bulk of the work for us, but we still have to make some important decisions: What do we buy? Who do we hire? Who do we delegate responsibility to?

Incidentally, these are very much "investment" decisions, so your background in this area will serve you well. "Invest" in a charity program. Set one up from scratch if none of the existing ones are satisfactory. Gather motivated and qualified people. But beyond that, the best thing you can do is keep working on the things you are best at. A "Web 2.0 AJAX social network blah blah blah application" might seem petty and trivial in the greater scheme of things, but it gives you more power to change the world then most people can dream of.

Imagine you really were a medical researcher and you find out someone you love has cancer. All-nighters can only do so much. You still need to run tests, hire assistants, get software and equipment. Chances are, you won't be able to cure the disease on your own anyway. You'd feel just as impotent.

The author of that book teaches the single most popular class at Harvard.

The field of "positive psychology" is maturing, developing real scientifically-backed theories on happiness and personal development. (a unignorable aspect of this, of course, is financial well-being, which is why many of us are here on news.YC)

If you're not doing what makes you happy, and have no plans nor desire to get out of this vicious cycle (I know, I've been there), then you will just keep spreading unhappiness to those you touch around you. (we all know someone who's constantly whining and complaining about things & being a constant downer to everyone)

Polywell is getting the most press and has the best pedigree - its inventor is Robert Bussard, one of the inventors of the Tokamak. He believes he's proved that a new design of his will work...his experiments were funded for 12 years by the Navy. Now he's trying to raise about $5 million for a couple more test reactors. After that though, he'll need about $200 million for the full-scale demo (vs. $10 billion for the tokamak). Given the money, he figures he's about five years away from a full-scale, power-producing reactor. Most likely, once he's proven the concept a little better, the money for the big reactor won't be too hard to get.

Focus fusion needs about $10 million total, some of which is already in the pipeline from a licensing deal. If it works, they're only about 3 years away, and a reactor would only cost $300K to build. They're less well-known but have some interesting results so far, and they've got an active research program going.

Both projects are shooting for boron fusion, which is harder to achieve than the deuterium fusion used by the tokamak, but is almost totally non-radioactive. And both projects believe they can produce power at about 1/50 the cost of fossil fuels.

Both have the potential to make a heckuva rocket, too...access to space for the middle class, manned trip to Mars in a couple weeks.

I really think this is our one shot to get out of the mess we're in. Without it our future looks grim...more and more demand for oil, with diminishing supplies, global warming, wars over the scraps. With fusion, it would all turn around.

If you want to save the world and kick off the biggest economic boom in history, all for just a few million bucks, give these projects a look. I've donated a little to both but I have way less money than Paul Graham.