I use google reader in an effort to more efficiently waste time every day. It's quite handy for RSS/news reading.
Every once in a while they change a feature here or there.. sometimes for the better, sometimes for the worse. The other day Scotty and I noticed that f5 no longer refreshed google reader.. instead it brought up a tagging box... and I noticed that If I hit f6, it'd make the left pane with the subscription list hide or show itself.
A week or so later, it quit both behaviors. I didn't like the f5 one.. (as I use it exclusively to refresh webpages) But I was kind of attached to the f6 one.
So I googled, and came across this:
Google helpfully documented all the shortcuts they've got. Also, you can view a cheatsheet while using google reader, by typing "?".
It looks like "u" was what I needed.