In Greece, until very recently, voting was obligatory, as in having both civic and penal consequences if you were caught not voting without a valid excuse. That no longer happens, but it is taken for granted that you must vote. There's no registering; everyone over the age of 18 automatically is given the right/obligation. I still don't get the registering process here in the UK.
Ever since learning about it, I've always bemoaned how the United States doesn't make it mandatory to vote. It's why there's such a low voter turnout - compare the U.S. to Australia, for instance, where I believe there is a day off to vote and it is compulsory, there is a 95% turnout (in comparison to just over 50% in recent years in the United States).
I also believe that jury duty is a civic responsibility. If you're on trial one day, you might appreciate the presence of the jurors, I'm sure. But that's only my opinion - if you don't like the system, go somewhere where you won't be compelled to participate in the jury selection process.
I think it's worse when people don't vote, and then complain about laws and bills that they disagree with, or how terrible life is because the government sucks. Voting means you're making an opinion - it's only one in however many are registered, but it still counts. You cast your ballot and disagree - THEN, you can be all righteous and cuss out George Bush and your Senator and your Representative all you want. If people are eligible to vote and do not even bother to register... they're not bothering to voice an opinion, and really shouldn't have a right to complain about how miserable the government is making their life.