Hey, I finally used the long term analytics. And I saw a weird spike in my traffin back in January.
When I zoomed in on the date, I saw that an iMac in the network was asking for many many many .local addresses with weird names.
Anyone seen this before? Any idea what it might be? I have not seen it since...
Google Chrome will throw out random domains to check connectivity. I think there's a FAQ about it here somewhere, but I just can't find it right now.
Quite possible Dan is right. My Chrome checked for updates...
Searched "random domain" and found this in the FAQ 
However, your spike seems extraordinarily high...