Somewhere around the 12th of Jnanuary, 2007, Eastlink started messing around with the IP blocks that they're handing out to residential customers. For literally years my IP address was completely static, and in the 18.104.22.168/16 range (I don't want to actually give it out in case it is ever given to me again ;)). Now, it's in the 22.214.171.124/16 range.
What's up Eastlink? Are you reorganizing things?