As you can see in my reputation graph, my reputation points on this site tend to stay pretty much the same for some days, then shoot up for a short while and then calm down again.
This is not because of my behavior: I was recently gone for a week, but other than that I've looked at reviews (since I can, mainly Mo-Fr) and I'm subscribed to two tags and answer most questions there.
But still my reputation has a wave-like pattern, first the interval was about 2 weeks, then there was a longer pause and then a boost about 10 days long. I neither see this pattern at other users, nor on other sites.
What could cause it? Just random chance?