Guess a number between 1 and 50,000 once you reach the pageviews? XD Closest number gets a thing. I'm bad with coming up with ideas for these kind of things.

I've celebrated my milestones with a raffle prize. People comment on the journal and I give them a number, then on the day of the draw I use a random number generator to pick a random one. For an added bonus, I tend to offer more prizes if more people join (20 contestants means two prize winners, etc.)

The raffle prize could be a story, since I see you do a lot of writing. ^^