I've decided to do the same! I've trawled through my Google calendar back to the start of 2011 and listed all the ones that are included (there are lots of other things that I ought to be doing, but this was a great task to help me procrastinate). I'm hoping that this will be useful - there have been occasions when I've had to take print boxes for both current talks, because I've not been sure it the club I'm visiting have already seen the first talk!
Now it's nearly time to go and make a cup of tea!