Marco Arment, famous for apps like Instapaper and Overcast, has just released his first Mac app. It's relatively simple but can have a profound impact on your productivity. Marco detailed the reasons for creating the original scripts in a blog post entitled Automatic Social Discipline.
Essentially, the app lets you specify certain applications to watch, an amount of time to check for inactivity, and whether you want to quit or hide that particular app. This is great for closing unnecessary apps in the background on your Mac while you're working. That way you can stop getting all of those Tweetbot notifications that might otherwise interrupt you.
I started using it today on my work Mac. Instead of killing apps, I'm choosing to hide the corporate email client. I think it's a visual distraction and, while I want it open to notify me of new email, I don't want it to stay up in case I forgot to close it.
I haven't set it up on my personal Mac yet, but I'm sure I'll be doing that soon.
If you're a Mac owner and want to try and remove some distractions in your life, check out Quitter. It's currently free on Marco's website.