So this is an idea I've been mulling over for a while now, and while I'm aware that there are flaws in it, I have to say that I think it's worth doing. Australia does it, and they seem to get along alright...
My idea stems from America's low voter turnout. Everyone knows that somewhere around 50-60% of US citizens actually vote. This is how George W. Bush got into office, basically; he took the very strong support of 30% of the country, made sure all those people voted, and then picked up about 10% of the undecideds. That only adds up to 40%, but when only two-thirds of the country vote, 40 out of 60 is 66%. (Trust me on the math here.) People aren't taking seriously their responsibility to vote--and it is a responsibility, as much as it is a right.
So let's make voting mandatory. Election days would become a federal holiday, but you would be expected, as a taxpayer, to get your butt down to the polling place and cast your vote. Obviously, this is going to create a bit of a demand on the system, which is currently geared towards not expecting many people, but I've got a solution to that: Punishment for failure to vote involves either fines, which would go directly towards purchasing equipment for the polling places, or community service, which would be done during the next election (as, you guessed it, a volunteer.)
I've heard a few objections when I mentioned this before, but most of them boil down to "I don't want stupid people voting." (Which seems to radically misunderstand exactly who the 30% of the people who helped put Bush into office are, but that's neither here nor there.) These people aren't stupid. Apathetic, perhaps, even despairing of the political process. But in the end, putting a boot up their backside and making them get out and vote is only going to increase their emotional investment and involvement in the political process. They'll be bound to become a little more aware of what's going on if they have to. (Perhaps not much, but it's not like there aren't plenty of people who walk in, vote a straight-party ticket, and walk out feeling like they've done their due diligence as citizens.)
Of course, the real trick is getting it passed. Obviously, no politician is going to go for it; they all like to make lip service about how voting is important, but as incumbents, they have more than a little attachment to the way things are. I say let's put it on the ballot as a referendum. Really, it's bound to pass...after all, the majority of people actually showing up at the polls are smug bastards like me who want to see voter turnout increase. And most of the people who'd be against the bill...well, they're not voting this year.