The Catesby Conspiracy (Or Gunpowder Plot) surrounds a man named Robert Catesby (1573 - 1605), and some of his Catholic supporters (Guy Fawkes, Thomas Wintour, John Wright, Thomas Percy) . The plot evolved from small acts of garnering Catholic followers, to rather significant acts of terrorism, in response to King James I imposing harsher penalties on English Catholics. The five met, and conspired, swearing an oath on the Holy Sacrament that they would blow up James and the House of Parliament. All conspirators had encountered some sort of trauma-slash-difficulty in life, with regard to their choice of religion.
It is believed that they attempted to dig a tunnel under the House of Parliament, based on their confessions, however there is no proof of this. (And of course, torture is torture, and naturally if you're tortured with skill, and thoroughly, you'd probably agree to being Sir Isaac Newton.). Popular belief has it that their tunnel became useless due to water seeping down into the tunnel from the river Thames. So, Thomas Percy acquired (exactly how he did this remains unknown) a cellar on the Parliament grounds. The conspirators placed 36 barrels of gunpowder in the cellar, hidden behind pieces of iron.
Meetings of Parliament met with repeated delays; the conspirators bided their time, during which some were forced to acquire additional gunpowder because their original stockpile was beginning to spoil, as gunpowder has something of a limited shelf-life. During this time, Catesby recruited additional help to his cause, in the form of various family members and servants.
An unknown letter reached the hands of one William Parker, Lord Monteagle (The Monteagle Letter) on 26 October 1605, stating, more or less, that he'd better not show up at Parliament in ten days, to avoid a "great calamity that would consume it." Monteagle delivered the letter immediately to Robert Cecil, the King's secretary of state. Almost immediately (due in all probability that the conspirators were, for the most part, gentlemen, and thus had reasonable power and wealth in British society), word found its way back to the conspirators. They began to accuse one another of sending the letter in the first place, but it did not daunt them from their goals.
On the night of 4 November, 1605, Guy Fawkes was caught with the gunpowder, and tools with which to create the "bomb" needed to blow up the Parliament buildings. He was arrested, brought before the King, and eventually tortured, revealing his part in the plot. News spread of his capture, and by morning, the conspirators began to leave London, bound for Warwickshire. They met, and barricaded (depending on your source; there are many for this part of the story) themselves in Holbeche House. The Sherriff of Worcester sieged them with a small party of men; Catesby, Wright and Percy fought, and were all killed. Rumours also abound that they were all drawn and quartered for their crimes.
Wintour's and Fawkes' confessions seem to be the only significant records of this incident.
Sources: History Television (unfortunately can't recall the name of the show), and http://britannia.com/history/gunpowder2.html. To be honest, I searched this out because, in Newfoundland, they still celebrate Guy Fawkes' Day, and I was interested in learning why.