Thanks, George. Yes, Churchill was at the Battle of Omdurman and took part in the famous charge of the 21st Lancers, often touted as one of the last full-scale cavalry charges of the British Army. If I recall correctly, out of a total of around 28 British dead in the whole battle, 22 died in that single charge. Between ten and twenty thousand Sudanese died, a testament to the use of state-of-the-art weaponry (smokeless powder, machine guns and armoured warships) by the British and Egyptian forces. Note that it was not "British rule" that was subsequently established, it was Anglo-Egyptian Condominium rule, although Britain was the dominant partner, at least until the Egyptian nationalist 23 July Revolution in 1952.
Thirty-odd years ago I got a guided tour of the battlefield from the colonel commanding the British Army Training Team in Khartoum. We stood on a hill overlooking the battle scene while he described it all in great detail, and walked down to the gully where the 21st Lancers met their match. Being able to see the lie of the land made it all more real.
If anyone is interested in reading a different angle on the battle from the normal British victory-and-glory versions, there's a very good account by a Sudanese historian, ʿIṣmat Ḥasan Zilfū, called
Karari : the Sudanese account of the battle of Omdurman. Karari is what the Sudanese call that battle. The book is out of print but is probably still available online from out-of-print booksellers.
Philip, as George says, Churchill was a bit of an adventurer in his youth (arguably also in his later years). In both Sudan and South Africa he was a war correspondent, although at least in Sudan he did hold a commission and was attached to the Lancers:
As soon as he could, Churchill charged off to take his part in "a lot of jolly little wars against barbarous peoples"... He gladly took part in raids that laid waste to whole valleys, destroying houses and burning crops. He then sped off to help reconquer the Sudan, where he bragged that he personally shot at least three "savages". The young Churchill charged through imperial atrocities, defending each in turn... Later, he boasted of his experiences there: "That was before war degenerated. It was great fun galloping about."
(
The Independent)
Incidentally, the Boer general who captured him was Louis Botha, I believe.