It does work.
Animate Dead and
Worldgorger Dragon (in the graveyard) 'combo' to produce infinite mana: each time the lands come back, they come back untapped and you can tap them for mana before they're exiled again. If there is another creature card in a graveyard, the loop can be interrupted by having
Animate Dead target that creature card rather than
Worldgorger Dragon. This allows on to use that infinite mana on sorcery-speed things too.
If no other creature card is in a graveyard and you can't do anything with that infinite mana at instant speed (and neither you nor your opponent can stop the infinite loop), then the game is a draw.
Of course, all of this also applies to
Dance of the Dead.