Here's one for ya'; get a blank piece of paper, a ruler and a pencil.
Rule out a set of lines on the paper. But do it slow and do just one line for each year of your life. Don't write anything, just remember each year as you draw out the line.
Getting your headspace right for year one might be a bit of a struggle, but it is amazing how much you can make yourself remember.
Also, don't freak out on how few lines there are, just make the most of the ones yet to be drawn.
Counting down from a million might just get to seem to be a waste of time, but don't let me rain on your party.