Just my personal experience, so take it for what it's worth.

Two types of feds during a shutdown; essential and non=essential. The senior mgmt at each agency determines what positions/personnel are essential or not. Essential personnel have to show up regardless of being paid or not. Non-essential employees are given four hours of pay on the first day of a shutdown to close out their work for the duration of the shutdown.

The shutdown is over when Congress fixes the budget. Either in the fix or soon after, legislation has to spell out how employees are to be paid for the shutdown.

During the last shutdown in 1995, non-essential employees were paid as if they had worked. Essential employees were also paid as if they had worked, because they had worked. There is no way to know what Congress will do, so if you are a fed and you want to make sure you will be paid, regardless of whether you work or not, it's better to be essential. If you don't mind a little gambling, and Congress has been pretty generous in the past, it would probably work out OK if you are non-essential (paid vacation),

This Congress is working on the FY 2011 budget which began on October 1, 2010. They should be working on FY 2012 budget which needs to be passed by October 1, 2011 (6 months). I haven't done the google-fu, but Congress has not passed a budget on-time for most of the years during my life time (born in 1964). Continuing Resolutions (CRs) are a way of life for most federal employees. Scrimp on expenses most of the year then blow it all in the last three months. Saving money in the federal budget is just asking Congress and the GAO to take your funding away.

This is not meant to be a justification for the way the federal government works, merely an explanation from my experience. Shutdown threats come and go but rarely does either party let them happen. The political trickle down is bad for everyone, especially when all they were arguing about during this last crisis-du-jour was a tiny percentage of the overall budget.

Both sides are gearing up for the real fights ahead, debt ceiling and FY 2012, FY 2013 budgets. It doesn't take an accountant to see where our current spending and revenue curves are taking our country.

Hope this helps someone. If not, please disregard my rambling.