Can'tFindThisVideoAgainFilter: YouTube, perhaps; within last 6 months. A couple of guys go back in time (!) and keep a diary. They return to the present and assert that birds are just dinosaurs. Pretty sure the punchline was something close to my tagline above. Much better than as described...
"Can you take me back where I came from, Brother can you take me baaaaaack, Can you take me back?" -White Album
GameFilter: Computer turned-based strategy game (one The Blue a while back?) in which you can recursively go back in time to change things...? [more inside]
Time&SpaceFilter: GoogleFu failing me here... Trying to RE-find specific time and amount measurement/approximation sites. [more inside]