This is pretty much low as low priority as bugs get, but I noticed something amusing when I was hitting Server Fault while the sites were offline.
The hot question list was showing totally the wrong icons next to the sites. Which made me wonder why photography was asking questions about atomic bombs, or why security.se was asking questions about the Terminator
I'm guessing it's because it's loading the CSS from one date, but the sprite from a different date. I'm guessing that adding new sprites to the bottom of the image only (instead of inserting new sprites in the middle) would fix this.