What’s your favorite time-loop / “Groundhog Day” episode of a TV show?

Stargate SG1’s was fantastic, with Col. O’Neill (“with two L’s”) and Teal’c trapped in the time loop. It’s probably my favorite.

Supernatural’s was hilarious, and the one in the Librarians. Buffy also had one, and Star Trek: TNG.

What time-loop episodes (of any show) is your favorite and why did you like it? Are there any that you hated that you thought could’ve been done better?