Many geocachers will, sooner or later, do things like filling their date grid and filling the D/T grid. However, as time goes by there are more and more cachers who have been in the hobby for ten or even fifteen years who will have done that a long time ago and are looking for more difficult goals.
Personally, I've been working on filling other calendars. I already have a complete calendar with only traditionals and a complete calendar with only mysteries. I'm slowly working on doing the same with multis, but there are too few around here so it goes slowly. I know others are working on the D/T grid using only one cache type.
When you've done the "normal" goals, what are you aiming at that isn't one of the standard targets?