The word "obligatory" should not be in your vocabulary. Yesterday was the 10-year anniversary of 9-11. An occasion of note, no doubt, but if you wanted to post about something else, you can.
Or you could be like Dave Weigel and revolt against the obligatory 9-11 post by...writing an obligatory 9-11 post.
I'll do Weigel one better. He writes:
Printed on and stacked, the where-I-was stories of 9/11 would reach past the moon. Some are interesting. Mine isn't.He then proceeds to tell you his not-interesting 9-11 story.
Mine isn't either...so I'll blog about something else instead!