Prized Finals Day places will be up for grabs when the eight teams left in the Friends Life t20 lock horns in this week's quarter-finals.
You can watch each of the four games live on Sky Sports, starting with a double-header on Tuesday as Surrey entertain Somerset and Durham travel to Northamptonshire.
Ahead of the action, we asked former England, Hampshire, Lancashire and Derbyshire all-rounder Dominic Cork who he thinks will make it through to Edgbaston on August 17...
Surrey v Somerset: 4pm, Tuesday, Sky Sports Ashes
Surrey turned in a really strong performance at Essex to earn themselves this home draw and they've now won three on the spin. But the quarter-finals are all about who turns up on this day - what happened in the Group Stages is very much in the past. This one should be a very good game. The Kia Oval is a very, very good ground to play Twenty20 cricket - it's a very quick pitch and Somerset are an experienced side with plenty of big-match players.
Steven Davies (228 runs) has impressed me at the top of the Surrey order and Jade Dernbach (14 wickets at 12.78) has bowled quite nicely, as has Jon Lewis with rather less luck. Surrey have very good bowling options all the way through their team, with Gareth Batty and Zafar Ansari providing decent spin options. They've got most bases covered and a good batch of all-rounders, including Azhar Mahmood, an experienced wicket-taker who has improved as a batsman after being pushed up the order in the IPL. Once he gets himself in he has proved that he can win games with the bat.
Jason Roy (244 runs) is a very exciting talent at the top of the order and Zander de Bruyn and Vikram Solanki are both dangerous operators who can take the game away from you with the bat but if they are going to qualify for Finals Day they need six or seven guys to produce on the day.
Somerset - runners up in 2009, 2010 and 2011 - have the pedigree to get the job done but haven't been able to get across the line since they won the trophy at the Oval in 2005. With experience throughout their line-up - even if Marcus Trescothick isn't fit - I give them the edge over Surrey on paper. In Craig Kieswetter (447 runs at 55.87) they have the competition's top run-scorer so far but there is plenty more firepower to come should he fail, not least in the shape of Jos Buttler (182 runs) who remains an exciting young talent and the ever-dependable Peter Trego (256 runs). Throw in the experience of Alfonso Thomas (13 wickets), who bowls exceptionally at both ends of the innings, Somerset should have too much.
CORKY'S CALL: Somerset haven't played Twenty20 cricket as consistently well as we know they can do this summer but although they away from home, I think we'll see them at Finals Day for a fifth consecutive time.
Northamptonshire v Durham: 7pm, Tuesday, Sky Sports Ashes
Northants beat Somerset to top spot in the Midlands/Wales/West division, winning seven of their 10 games, and their success hasn't surprised me even if they aren't a team of box office names. They've played good cricket throughout and Muhammad Azharullah has been in superb form - he's got the ball to swing early on and has also got it to reverse as well; his 23 wickets at a fraction over 10 apiece make him the most successful bowler in the competition so far.
Well led by Cameron White (269 runs), Northants are a good team unit and clearly have an excellent spirit within the camp. I do like David Willey's bowling - he's very similar to his father in as much as he's a very aggressive cricketer and left-armers in general tend to be that little bit more difficult to get away in Twenty20. Don't forget that Willey can bat too, so it's no wonder that England are keeping an eye on him.
In Durham, Northants are up against a team that is revitalised under the captaincy of Paul Collingwood. They too have got dangerous cricketers at the top of their order - left-hander Phil Mustard (333 runs at 33.30) has limited-overs experience with England behind him and is a very difficult batsman to bowl at because he covers his stumps and targets the leg side.
Durham are picking up momentum at the right time of the competition and I've no doubt their players are looking at the draw and thinking 'we've got a good one, here'. Northants won't be pushovers on their own patch but if they could have picked their last-eight opponents then a trip to Wantage Road would have been high up on their list.
CORKY'S CALL: I'm going to back Durham to win this one quite simply because man-for-man I think they are the stronger side.
Watch all four of the Friends Life t20 quarter-finals this week on Sky Sports Ashes then make sure you tune in for Finals Day, at Edgbaston, on Saturday August 17.