Max Scherzer, especially this season.
Not known nearly well enough fact: He's the active leader in career strikeouts per 9 innings.
And this season, he's walking about 1 batter per 9 innings pitched. Simply amazing. He's got a K/BB ratio of nearly 10, only two other pitchers have a ratio above 6.5.
He's gone 7 with 2 or fewer earned runs in 13 of 17 starts, so you feel pretty good about your chances of seeing a masterpiece of a game.
Guy won't wow you with huge breaking balls, but he makes hitters look silly with a wicked fastball-change-up/slider combination.
Only Zack Grienke is having a better, or more consistent season, but he's not as exciting to watch in my opinion. I'm also a homer Nationals fan and if you go to a game I've probably jinxed you into watching a dud.