Time is a terrible thing to waste.
Do you ever interrupt your work and go on the web for just a minute, only to find yourself 20 minutes later in the bowels of the internet, having forgotten what it is you were doing?
Well, no more. Introducing Crastinator Pro Mac edition.
This handy bash shell script that quietly runs in the background, will start a timer when it senses that your foreground application is Safari/Firefox/Chrome. After that it will verbally harass you at preset and user-controllable intervals of time until you switch to another application.
Special behavior can be configured for browsing "useful" sites, like gmail.
To run, in Terminal type:
chmod +x crastinator-pro.sh ; ./crastinator-pro.sh >/dev/null 2>&1 &
And set your speaker volume to be nonzero.