[1] 147 is the maximum number of points you can get in a game of snooker. The only way to do this is to alternate pocketing a red ball then a black ball until all red balls are off the table; this nets you 120 points. Once this is done, you need to pocket the remaining colored balls, ending with the black ball, for an additional 27 points. All this must be done without conceding a single point to your opponent (i.e., no mistakes). Start watching from 1:10 for the action.
One of these is not like the others. I'm as big a Ronnie fan as any body else, but Snooker is less physical/athletic than any of the other sports in that list. I am not discounting the skill by any means, however - Ronnie in full form is unlike any other snooker player, perhaps except jimmy white.
Heck, I'm not huge sports fan, I can come up with half a dozen more impressive feats in sport off the top of my head.
* Beamon's long jump record in 1968 Olympics: https://www.youtube.com/watch?v=DEt_Xgg8dzc
* Maradona's goal of the century: https://www.youtube.com/watch?v=1wVho3I0NtU
* Zidane CL final, won Real Madrid its 9th CL title: https://www.youtube.com/watch?v=rFfomw-Z4uE
* O'Sullivan, fastest 147[1] in history (snooker = 4D chess in my opinion): https://www.youtube.com/watch?v=M3C7I5lRZII
* Sotomayor's high jump world record in 1988 Olympics (his lowest time and still 0.01 m higher than anyone else since then!): https://www.youtube.com/watch?v=7n6NhV4CaiU
* Usain Bolt
[1] 147 is the maximum number of points you can get in a game of snooker. The only way to do this is to alternate pocketing a red ball then a black ball until all red balls are off the table; this nets you 120 points. Once this is done, you need to pocket the remaining colored balls, ending with the black ball, for an additional 27 points. All this must be done without conceding a single point to your opponent (i.e., no mistakes). Start watching from 1:10 for the action.