Now, if there's something I am, it's an excel nutcase. I use it to keep track of everything, from uni timetable to writing. Incidentally, it is the last one I am interested in today. There are several spreadsheets available online to do with tracking your writing achievements/goals. Since I am so particular, I didn't like any of them. So, being the person I am, I decided to make my own. And here they are!
The NaNoWriMo Spreadsheet
This one is to track your progress both during NaNoWriMo and to help you set a goal for subsequent months. Simply plug in your wordcount for the day and your goal for the given month, and the spreadsheet will do the rest for you. For continuing projects, there is the existing wordcount box, which lets you plug in the words you already have so as not to mess up the average words per day box or the 'Daily Goal' column.
The Writing Log
This one is for those who don't need a goal, or who can't be bothered to write every day. Plug in the date in dd/mm/yyyy format and your total wordcount, and watch the percentages climb. You can customise the daily wordcount goal, but it won't affect any other part of the spreadsheet. Your total wordcount goal is just a point of reference and a way to calculate the percentages, giving you something to shoot for.
A couple more things before I go and actually do some writing. Please do not mess with the formulae unless you know what you are doing. Otherwise excel could have a spaz attack and spit out error messages. If you find any errors (the spreadsheets haven't been tested by anyone other than myself) please let me know and I will fix them. Enjoy!