One must watch in awe, of course, at the SO users with the highest reps, many tens of thousands. But for the rest of us, smaller achievements are still worth celebrating :-).
I just crossed the 1000-point milestone on Stack Overflow today and was walking around with a bit more spring in my step. In fact, the first thing I did when I arrived at my office was to send out a department-wide meeting invitation for a combined cubicle-warming (it's a long story) and SO milestone celebration for myself. The meeting was scheduled from 10:55 to 10:59 -- yes, I do mean four minutes because folks are just rather busy nowadays, and I thought could catch more people in the gap between other meetings.
It was great fun; I served snacks; I shot some video of it; lots of colleagues walked by to offer congratulations; a few even knew what Stack Overflow was (I and others eagerly espoused praise for SO to those that did not.)
So my question is: what have you done to celebrate your SO milestones?