I really love the FitBit and particularly it's ease of use. Just remember to charge it once a week! The fact that data can be uploaded wirelessly when you walk within 15ft of a base station makes it incredibly easy to collect data.
I recently presented to the Washington DC Quantified Self Meetup Group and did a simple comparison of steps travelled during four events I recently attended. You can see the presentation on SlideShare here.
I have been wanting to do more with Fitbit and so I finally got to play with the Fitbit API. There is a great article at QuantifiedSelf.com by Ernesto Ramirez that gives you a great step by step guide to integrating Fitbit with Google Spreadsheets. Check out:
After registering on the Developer site at Fitbit.com I was able to create an application hook and grab an application Secret and Consumer Key to add in to the great piece of code provided by John McGlaughlin.
After following Ernesto's instructions I was able to download my data from Fitbit in to a Google Spreadsheet. Then by using the ImportRange function in Google Spreadsheets I was able to download two separate sets of data (for different users), merge the results in to a single spreadsheet and chart the comparative results.
Pretty cool for an hour's worth of dabbling.
It got me thinking about using the PHP scripts for the FitBit api that would integrate with Alan Viar's RESTCat activity tracking server and then building a similar script to grab data from RESTCat to import in to Google Spreadsheet for quick and easy charting.