I also have games not played from steam sales, maybe even as far back as last summer. Yet I still bought more. Steam says I have 347 games on it. They really need a fecking fliter to remove games from your search that you already own.
One of my sales purchases was prison archtect, only played the tutorial and a fast attempt at a small prison but it seems really cool. Had no idea what the point of the buying prisoners is though. Do they appear in everyone else's game?