Death doesn't need to stop you from doing all the things you enjoy, as long as the things you enjoy are pretty basic. Certain bodily functions continue for minutes, hours, days, and even weeks after death. You will not believe the kind of things a dead body will do with its now-copious amount of time.
By the way, this post is not for the weak of stomach.
10. Nail and hair growth (by technicality)
This is a technical function, not an actual function. The body doesn't produce more hair and nail tissue, but both of these things do 'grow,' in the days after death. What actually happens is the skin loses moisture (although cosmetics companies are probably hard at work making a cream for that) and pulls back, exposing more hair and making nails seem longer. Since you do measure the length of hair and nails from the point where they meet the skin to the tip of the hair, the hair does 'grow'.
9. Brain activity (with drugs)
One of the side effects of modern technology is a blurring of the time between life and death. The brain can be almost completely gone, but the heart can keep pumping. If the heart is stopped for a minute, there's no breathing, and the person was dying anyway, most doctors just pronounce people dead while their brain is technically still alive for the next few minutes. The brain's cells spend those minutes scrambling for the oxygen and nutrients they need to stay alive - to the point where they often damage themselves irreparably even if the heart starts up again. Those minutes before the damage is too extensive could be extended, with the right drugs and under the right circumstances, to days. Ideally, this would give doctors a chance to save you, but it's not guaranteed. I know what most of you are thinking, "What fun! The biggest problem I had with dying is that it could be quick and painless, with no chance that my living brain is stuck inside a corpse for days on end." Well, now you don't have to worry about that.
8. Skin cell growth
This is another function of different parts of the body dying at different rates. While loss of blood circulation can kill the brain in minutes, other cells are not as in need of constant care. Skin cells, which are used to living on the outskirts of the body and grabbing what they can through osmosis, can stay alive for days. Its a good thing they don't have brains, or I'd feel sorry for them, the poor doomed things.
Peeing, we think, is a voluntary function. And we're mostly right, except if something's really funny. Not-peeing, though, is not a voluntary function. We never have to think about it, because a certain part of the brain is always in charge of it. This is the same part that's involved in regulating a person's breathing and heartbeat, which is one of the reasons people tend to pee involuntarily if they're drunk. The part of the brain that keeps the urinary sphincter closed is inhibited. (More alcohol will shut down the part that regulate breathing and heart function, which is one of the reasons too much alcohol is dangerous.) Although rigor mortis stiffens the muscles, it doesn't set in until hours after death. Just after death, muscles relax, causing people to urinate after death.
We all know that in times of stress the body eliminates waste, often in front of people or on camera. The body relaxes certain muscles and things just . . . progress. In the case of dead bodies, the whole thing is helped along by the gas that's produced inside the body. This can happen hours after death. Hours. Considering fetuses can also poop in the womb (it's true!), this may be both the first and last thing we do in life. Puts things in perspective, doesn't it?
It turns out that when you die, bot only are you expelling stuff, you're actively making more. Or, at least, something is making more. We forget that we share our bodies with tons of other creatures, many of them beneficial. The bacteria inside your gut don't die just because you do. While plenty of them are parasitic, some of them are great aids to digestion, and do part of the work for us. They keep right on chugging, even when we're good and dead. Others eat into the lining of our intestines, making more of that gas that repulsed us all in section six, which pushes things along.
4. Erections and Ejaculation
When the heart stops forcing the blood around the body, it pools in whatever area is lowest. Sometimes people die standing up and sometimes people die lying face down. I think everyone here has enough spatial reasoning to understand what kind of blood pooling that would encourage. Meanwhile, for all that talk of relaxing muscles after death, it doesn't last forever. Certain types of muscle cells are activated by calcium ions. After activation, the cells expend energy putting the calcium ions back outside the cell. After death, the membranes become more permeable to calcium and the cells don't expend as much energy to push the ions out, so the muscles contract. This does lead to rigor mortis and can lead to ejaculation. It's real. It happens. Now let's never think of it again.
3. Muscle movement
Although the brain may die, other areas of the nervous system may still be active. Nurses report seeing reflex action, which involves nerves sending signals to the spinal cord and not the brain, leading to muscle twitches and spasms after death. Some even say they've seen shallow chest movements after death. (Although maybe the doctor fell down on the job for that one.)
Our bodies are basically sacks of gas and goo supported by bones (which are filled with yet more goo). Rotting happens when bacteria go to work and the proportion of the gas increases. Since we carry most bacteria inside our body, the gas builds up inside. We've seen several ways it takes out. One of those ways is through the windpipe. Since rigor mortis stiffens all the muscles, including the ones that work the vocal cords, the combination leads to some very eerie sounds coming from dead bodies. People hear moans, groans, and squeaks coming from the dead, although why they stay around to confirm that the bodies making them are truly dead instead of peeing on the floor and running for their lives is beyond me.
1. Giving birth
Oh. Holy. Hell. No Twilight scene could be worse than this. Back in the day when people dropped like flies, a number of women died while pregnant, and sometimes in times that were too cold to give them a burial. This gave rise to a charming little term called 'coffin birth.' The gases building up inside a body, combined with the softening flesh, were said to cause the body to expel the fetus. These events were rare, and caused a lot of rumors, but were documented in times before proper embalming and quick burial. It sounds like the kind of thing out of an Edgar Allen Poe book, but it did happen. And it's yet another reason to be happy that we live in the modern world.
Enjoy your leftover turkey. Try not to think about what it might have done after it died.