Psych, Season 8, Episode 3 ,"Remake A.K.A. Cloudy... With a Chance of Improvement", was a remake of the Season 1 Episode "Cloudy... With a Chance of Murder".
The wikipedia entry says it is "the first-ever remake episode of the series".
What about other shows? Has any show done it before?
(I'm more curoius about remakes happening within the same series than a remade episode in a remade series.)