Lots of bug fixes today, 27/01/2013, if you've been having trouble with this in the past please give it another try.
Updated for 2013 - large 'My Finds' (8000+) should now work. Let me know if you have any trouble.
Now with added Michael Fish!
This web app will generate a heat map of your geocache finds (see image on the right)- you'll need to be a geocaching.com member with a 'My Finds' file to use it.