The other day, I noticed a few items in my Facebook stream that I hadn't "Liked". I figured it was a glitch of some sort. Then it happened again today. I went and looked at my pages and there 10 or so pages I was subscribed to I'd never seen before and would never subscribe to. For instance, I found myself a fan of Phil Fischer, a Christian musician that just completed The Tea Party Song and is asking his fans for $113K so he can get it played on Christian radio. I emailed him to ask if he knew how I had ended up liking his page, and will update when I hear back. If you check his Facebook page, this seems to have happened to other people as well.
I couldn't find much else online about this happening to other people, except for this post on Facebook support. If this happened to you or you see any other info about it, let me know because I'm curious.