The first two got underway this morning.
The first two quarter finals of the World Snooker Championship are underway at the Crucible in Sheffield
It's 1-1 between defending champion Judd Trump and Kyren Wilson
while on the other table, Mark Selby and Neil Robertson are still playing the first frame.
This afternoon at 2.30, five-time champion Ronnie O'Sullivan will face three-time champion Mark Williams and Anthony McGill takes on Kurt Maflin
Those matches are all best of 25 frames.