I have been working on a piece of software that aids in mindfulness, It's an open source project so you can inspect and see it's virus free, or compile it safely for yourself (It's written in C#, using Visual Studio 2010), It's essentially a simple reminder, and let's you choose how often it's displayed. I know I spend way too much time online and often get lost in youtube videos and whatever else I happen to be doing, and this is why I made the program, I hope someone else can benefit from it as well.
Right now It's still in beta and I imagine there will be many bugs, as I'm just releasing it today, if you find a bug, please report it, either on the website, or here. I will fix them as quickly as possible.
Here is a link to the website: http://bawk.org/mindfulvisions/
Here is a link to the source code: https://github.com/jscix/Mindful-Visions