Ankh-Morpork's city racecourse, also known by its obselescent name of the Hippodrome, is located in upmarket Ankh, on the corner of The Ridings and King's Down close to the Dark Gate. Given the antiquity of the old name, which reaches past Latatian to an older language still (possibly related to classical Ephebian), it would appear that a racecourse or public arena of some sort has been hereabouts for several thousand years.
Horse-racing still happens here, making it the natural haunt of people like Doughnut Jimmy.
Language and antiquity:-
"Hippodrome" comes from Greek roots combining the word for horse - hippo - with the term for an arena where the public gather to watch entertainment. It is perhaps unfortunate that hippo has other symbolic meanings for Ankh-Morporkians, and its original meaning of "horse" has been lost in the mists of time. This may cause confusion to the ill-educated and hard-of-thinking..