USA Today explains how a "government shutdown" in lieu of a budget agreement is probably not as bad as you'd think:

If Congress doesn't pass a new spending bill in the next week, the federal government will shut down on Oct. 1.

An estimated 59% of non-defense federal employees would be exempt from the shutdown and would go to work as usual, according to a USA TODAY analysis of 119 shutdown contingency plans filed with the Office of Management and Budget.

Among them: political appointees, law enforcement, most overseas foreign service officers and anyone else deemed necessary for health or safety of people or property.

That last category can account for a broad cross-section of federal employees, because positions that support a key function — such as information technology, security or even legal help — are also protected. Even a receptionist responsible for picking up sensitive mail deliveries could be considered essential and exempted from furlough.

ICYMI: Becket has all the details about the looming shutdown deadline here.