A Million Dollars
Note from JSP: I wrote this in response to a message board post in which someone asked, "What would you do if a million dollars just fell out of the sky into your lap?"
Although denominations of up to at $10,000US have been printed in the past, the largest monetary amount used in US currency as of this writing is $100US; larger notes, while still legal tender, are out of print and circulation and have been since 1969 - as such, it is unlikely that they would be available for this, applying terms as realistic as possible to an event which, in this case, hinges entirely on the impossible. I am assuming, for our purposes, that we are talking about paper currency, and so the amount will have to be in the largest amount possible, in this case $100US. One piece of United States paper money weighs about (1) one gram; one million dollars (in hundred dollar bills) all together, not including any of the paper bindings that usually holds money together, would weigh approximately 10,000 grams, or 22.05 pounds, rounding up. We then run into another problem: The money would need to be collated in some fashion, as simply dropping loose bills from a great height would obviously cause them to be hopelessly scattered when they hit the ground. The standard method of holding large amounts of money, in movies anyway, is a briefcase. For our purposes, we'll say that the hundred-dollar bills have been neatly folded and stacked inside a tasteful Samsonite leather attache (model 356-SAM to be exact, if you're curious), which weighs 2948.35 grams on its own, or six and a half pounds. The money and the case together would work out to 12948.35 grams, or 28.55 pounds. An object that weighs this much, and a shape with as much air resistance as a briefcase, would need a little while to achieve terminal velocity.
Meanwhile, given that matter cannot simply pop into existence, let us assume that the briefcase full of money came from somewhere - the most likely culprit here would be a passing airplane in which someone has either comically bad luck, or extraordinary aim. This would be at about cloud level, which is roughly 2.5 kilometers or about 1.55 miles on average, give or take.
In order to meet all the requirements given by the question, I would need to be sitting down (as has been pointed out many times already, you haven't got a lap when you are standing), assumedly in an open space. Another complication arises from the fact that I would need to be sitting on something - let's say it is a metal folding chair.
I paid a lot less attention in physics class than I probably should have, so I am, I fear, unable to tell you exactly how hard the briefcase would hit when it landed in my lap. I can tell you, though, that human bones (even strong ones like mine) break when at least eight pounds of pressure per square inch are applied. The effective weight of a nearly 30-pound briefcase when dropped from a mile and a half would, in all likelihood, at least reduce my femurs to bone splinters. It would also most likely pass through the chair under me, meaning that my upper legs would quite possibly be reduced to paste. A less likely complication of this would be shrapnel - those shards of what had been my legs would have to go somewhere. In all fairness, they would probably only cause flesh wounds which would be, well, trifling compared to what was happening above my knees, but I felt I should mention it anyway. In addition to being not terribly fun to watch, this would also result in the ripping open of the femoral and possibly common iliac arteries on both sides of my body, which would begin spurting in earnest.
So, to answer your question: I'd die.
In the recent entry titled "A Million Dollars," entry number 448, it was stated that I did not know how fast the briefcase mentioned would be traveling. Thankfully, a thoughtful reader by the name of Tone P., whose head is far better with numbers than my own, wrote in to tell me that the briefcase in question would hit at roughly 494 and a half miles per hour. Which seems to support the "I'd die" theory quite nicely.