Read Bright's post below before reading the following...

In my personal experience, the humble toilet seat can give the kind of adrenaline rush only sky-diving, nude, while attached to some kind of rabid hyena and high on LSD, could possibly provide. Example:
My mom gets a new toilet seat while I'm away. I come home, arriving late at night, tired from a long days travel and fall directly into a deep and comforting sleep. The morning comes, the dawn breaks, birds sing as I awaken, like some kind of Raphaelite Figure, the exquisite light highlighting my chiseled yet angelic features. I stumble (but still in an attractive manner), not entirely awakened, toward the Smallest Room. My mind barely registers the new toilet seat, slow-witted as I am in the morning. After lifting the seat and beginning the untangling of the boxers I gaze upward, outside the window, in that "staring into the middle distance" thing all guys do at this point in the morning.

Here time slows down and several things begin to unfold. I will attempt to explain chronologically, but bear with me as it's all a bit hazy.

1) The toilet seat starts it's descent. Obviously designed by some penis-hating person, either a Feminazi or someone unhappy with their allowance of wang, the toilet has timed it's descent to take place at the exact moment I look away and have had enough time to "unleash". I notice it's guilotine-like descent out of the corner of my eye.
2) Instantly, I mentally begin sweating bullets and the future lives of each and every of my sperm flows through my mind like burning ice. Had I but the time, I'm sure a tear would have been brought to my eye as I recounted the many Doctors, Noted Philanthropists and esteemed Cambridge Scholars that potentially lie within my love sacks. No more than a quarter of a second has elapsed as yet.
3) I begin, in my mind, rehashing all the good times my member and I have had, the bad times we've been through, the many escapades and adventures we've not had time to pursue. God, I almost feel a song coming on.
4) Mentally preparing myself for the end of my existence as a male, I bid my penis and paraphenalia adieu, resigning myself to life as a hermit half-person that lives of the outskirts of humanity. Were this a movie, I'd be throwing kisses from the train as the it began it's slow chugging movement from the Station of Testosterone, my wang left on the platform, crying softly into a hankerchief.
5) At peace now, I look heavenward, my atheistic tendencies forgotten for a second and mutter "If it is your will...", before bowing my head, resigned to the loss of what critics a hundred years from now would still be calling "The Wang Time Won't Forget" and "the most beautiful piece of Natural Art to grace the English soil".

Obviously, this all took place in my mind. The real world cause-and-effect chain was somewhat simpler.
1) My penis's sense of self-defense fires a thousand Spider-sense type neurons in my brain. I combat roll backwards. Well, I attempt a combat roll. Okay, I fall over, the seat having missed my most prized possession by scant millimeters.
2) I hit my head. And begin cursing. Loudly. Regrettably, this brings my family.
3) Amidst all this a golden arc of what, regrettably, isn't sunshine rains shortly down. This is quickly stemmed, but not quickly enough.
4) My mother and brothers are outside the door, asking "What's wrong?". I answer with curses.

My dignity lost (and the tale recounted many, many times to various family friends and members by my mother and brother) but my penis intact, I end my story.
The moral of the story is either invest in some form of genital protection or don't buy man-resistant toilet seats.