Have you ever felt the need to integrate the tennis calendar with your own? Well, now you can! The calendar you see below has all the ATP and WTA tournaments for 2013, including information about tournament category (250/500/M1000/GS for the men, International/Premier/P5/PM/GS for the women), surface, and exact dates (including Sunday starts or Saturday finals).
If you're using Google Calendar, you can add these calendars (ATP and WTA separately, for those who only want one of them) to your schedule with a couple of clicks; if you're using a different calendar, you can import it in XML or iCal format. Or, you can just use the calendar in this post, if you wish!
Enjoy, and let me know if there's anything else you'd like to see here.