USnow covers the gravestones in Section 60 of Arlington National Cemetery in Virginia after sunset two days before Christmas day in Arlington, Virginia, December 23, 2009.Estate taxes affect very few people, but for those with seven- or eight-figure estates that are impacted, the end of this year is a crazy, crazy time.

That’s because going from a year with no estate tax (as 2010, oddly, was) to a year in which the estate tax is back (but with a $5 million exemption and large gifting possibilities) raises all kinds of quandaries for those who are very ill and for their families.

What if staying alive another week would save tens of thousands of dollars in state estate tax because the elderly person had already used up the gifting possibilities for 2010—but not for 2011? Or, if dying after New Year’s, rather than before it, meant paying the Treasury tens of millions more tax? The possible scenarios of spouses and children, second wives and estranged children, large sums of money, and elderly relatives on life support could make a movie.

Cheryl Hader, an estate attorney at Kramer Levin Naftalis & Frankel in New York, has more than one client confronting this year-end madness. In one case, it would be better for the client, who is on life support, to live till 2011 because of state estate tax payments that would be due in 2010, but could be avoided in 2011. In another, it would benefit the heirs if the man was taken off life support, as he requested in a medical directive, so as not to live beyond the no-estate-tax year.

“Whether somebody dies December 31st or January 1st makes a huge difference because the rules changed so quickly,” Hader says. “In some situations it pays to live, and in some situations it pays not to. Its such a bizarre topic that you’re never going to see it come up again.”