To date, not a single one of the 12 appropriations bills required to fund the government have been signed into law. Among other things, this means that as of midnight tonight, there is technically no money available to pay the salaries of federal employees (including Members of Congress and their staff), pay the utility bills for government buildings or fund grants made by the federal government.
The IRS is closed
Finally, it should be noted that this appropriations impasse is unrelated to the upcoming Debt Limit debate that will ensue in a few weeks. Like the Appropriations problem, the failure of the Congress and the President to agree on legislation raising the Debt Limit could also result in a government shutdown.