My friend Andrew introduced me to wunderlist when we were working on a project together.  At the time, I thought it was neat, but now I know that it's AWESOME.

Wunderlist is a task management tool that syncs across multiple platforms and even has a smartphone version!  I use both the Mac OSx app as well as the iphone app.  I enter tasks in a variety of lists, entering in rough dates i hope to have each task done by.  Every day I pull up the app and open it to the "today" tab to see what's on my agenda.  I can feel pretty good about myself when everything on the "Today" list is checked off, and I can move to tasks I didn't set dates on.

Wunderlist is also cool because you can share lists with other people, and it syncs straight to my phone.  Note I have a grocery list on the right.  I can add stuff to it as i think of it, and then when i'm at the store i can load it up and not forget a thing.  Pretty sweet!