Clash - is the episode featuring the introduction of Captain Marvel and the clashing opinions of justice as well as the thoughts of justice in the justice league.
Flash and Substance - is a flash oriented episode which covers many of the flashes villains and goes over his reason for acting the way he does/personality.
Wild Card - is a Joker oriented episode which covers the last VA appearance of Mark Hamil as the Joker. it's a two part episode that covers the origins of the Royal Flush Gang and actually features the VA's of the Teen Titans in it as members of the Royal Flush Gang.
all of them are epic.