Retire the chalkboard, and let your phone keep track of the score.
One problem with playing darts is that you have to do a bunch of addition, every time you play -- which, since dart boards are typically in bars, just gets harder as the night goes on.
But you have a companion that can easily do math, despite how long you've been playing darts. Let Cricket Scoreboard do the math for you.
The app supports cricket scoring, for two players or three. (The three player game uses the "cutthroat" variant of cricket, which is more fair for more-than-two players.)
A problem with other dart scoring apps is that they're turn-based; ie, you enter what you hit, then it tells you that it's the other player's turn. If you don't hit anything, you have to tell it that. Since hitting nothing is a pretty frequent occurence (at least for me), I want that to be nice and easy: just do nothing! So with Cricket Scoreboard, if you hit two 20's and a 15, just tap the "20" twice and the "15" once, and then tap your score -- whether you're the red team or the blue team. That saves time and taps.
Alternatively, you can tap the dots directly to light them up and notify your phone that you hit something -- it saves a tap!
It's available for Android, for free: