According to the schedule, they are re-running this episode opposite Dollhouse and Caprica over on the WB CW. It's notable for a couple of reasons:
It's a really good episode
It's written by Geoff Johns, who wrote the Smallville "Movie" Total Justice that is airing next week.
So I'm rerunning the review I wrote of it last year. Don't sweat it, I'll also have Batman and a new Smallville review up tonight as well.
Okay. This is going to be a quick one. Impressive. Geoff Johns, noted comic writer, wrote this episode of Smallville and in doing so, he managed to address Smallville's noted departure from the Superman mythos, throw easter eggs and metacommentary in while maintaining and extending the Smallville universe. RECAP (minor spoilers)