Minecraft has the option to check "Minutes Played" in statistics. The only flaw is that the time resets every update. It also is different on every computer you play on! I think they need to make it to where the time saves when you patch your game, and that the statistics and achievements should be saved online! Since 1.4.2 Came out I already have a day of playing time, and I know play nearly as much as I used to. I would have around ATLEAST 3-4 months of playing time if it saved. PLEASE JEB!