As of now, the US Congress has until April 8th, 2011 to decide on a budget for this year. Tensions are high and people are quite worried. The shutdown could potentially have wide-reaching effects, depending on how long it lasts.
Currently, there is a massive, ongoing battle on Capitol Hill concerning the budget. So far the federal government has been financed via six short-term resolutions since the beginning of the 2011 fiscal year.  All this time, however, there has been deliberation over budget cuts. Republicans and Tea Partiers, who are worried about the debt, want to cut funding to social programs and Democrats seem on board. So far, “Democrats have offered 33 billion dollars in spending cuts for 2011, while Republicans have approved legislation trimming spending by 61 billion dollars.” It should be noted that this is only in the Senate. Over in the House, there has been a proposed budget cut of $62 billion. 
The government shutdown could have serious effects. It “could mean that government workers would stay home, national parks and museums would close and cleanup at toxic waste sites would stop.” While this may not mean much, it could have unfortunate economic effects. The Washington Post states:
The impact would depend on the closure’s duration and on whether furloughed federal employees were eventually paid for their time out of work, as they were after the last shutdown, 15 years ago. If the estimated 800,000 workers did not receive back pay, the damage would be compounded as many families pulled back
Today, there are approximately 2.7 million federal employees.  Each one of these employees contributes to the overall economy and also pays taxes. If the a government shutdown were to occur and the furloughed employees were unable to receive back pay, then it would damage both the economy and the government as the employees would neither be out spending money or paying taxes. If a federal shutdown were to go on for a medium to long term, it could force families to reach into their savings until they are near or fully depleted.
Also national parks bring in considerable amounts of money. In 2009, national parks bought in $84.5 million in revenue and $78.5 million last year.  On average, national parks bought in about $215,000 on daily basis on 2010. That, too, would be lost if a medium to long term or even short term federal shutdown took place.
One strange part of the federal shutdown is that the government attests that a shutdown will not affect essential things, such as national defense. However, while the Pentagon “has already offered assurances that operations in Iraq, Afghanistan, Libya, and Japan would not be affected,” there is no such stance on troop pay. Yesterday, Pentagon Press Secretary Geoff Morrell was asked about whether or not troops would continue to be paid, he responded by saying “'I don’t have a definitive answer … to relay to our forces in Iraq or Afghanistan.'” 
At the end of the day, what needs to be realized is that when it comes to budget cuts, the only difference between the parties is the amount each wants to cut. Thus, both sides should be willing to compromise and do what is best for the American people, rather than have a useless battle of wills.