YouTube user twilight1138 has created this painful video that has the first two seasons of Captain Kirk's Star Trek all playing at the same time.
If you wanted to re-watch the classics but couldn't find the time, here's your chance. 56 episodes, the full first 2 seasons, simultaneously, and with sound! You'll be finished in no time ;-)
Done with a little bit of python, avisynth, and a lot of time. I replaced the season 1 episode 1 pilot by the first episode of the third season, because it was too long.