#22 Justice League Unlimited: The Once and Future Thing: Time Warped
The DC Animated Universe spanning Batman, Superman, Batman Beyond, and the Justice League Series had one huge omission. In that universe it was Kyle Rayner that received the ring from Abin Sur, and there was no Hal Jordan! That is, until a time wrinkle briefly rewrote reality with Hal Jordan being the Justice League's Lantern. Sure it was a brief moment, but the DCAU just wouldn't have felt complete without him. The rest of the episode ain't bad either as we learn of one possible future for John Stewart as it is revealed he is the father of future Leaguer Warhawk.
#25 - Justice League Unlimited: Initiation - John Stewart's new look
#24 - Batman: The Brave and the Bold: Death Race to Oblivion! - Guy Gardner's Lanternmobile
#23 - Justice League of America: Pilot - Doesn't air
#22 - Justice League Unlimited: The Once and Future Thing: Time Warped - Hal Jordan joins the league