Wizard of Oz on Family Guy

When the Tin man found out he was gay.

When Meg was Hot

Season4, episode4.
Meg gota afree makeover from Channel five and became a good looking and snobby/annoying bitch.
SNL was also on this episode.
Unfortunately her good looks didn't last, she said it was difficult being pretty.

If Lois Married Quagmire

See full version on season 5 episode 18.
Peter asked death to take him back in time so he could re-live his youth.
When he went back, he altered the course of events and ended up marrying another woman while Lois married Quagmire.
He fixed everything again though

3D Future Family Guy.

Stewie and Brian travelled to the future to witness this.
Family guy cartoon is shown as 3D family guy, and things have changed. Joe is a cyborg and Quagmire is half-man, half-frog.

Giant Crab In front of Peter's House.

This is on Season 10 episode 6.
The giant crab stops people from entering Peter's house.
I found it very funny.