Phineas And Ferb: Season 1, Episode 28

1 - 28: The Best Lazy Day Ever

Phineas and Ferb decide to spend the day doing absolutely nothing, but Candace doesn't believe them and ends up constructing something of her own, in an attempt to get them to take over for her, letting her bust them. Meanwhile, Doofenshmirtz invents an ugly-inator so he will be more handsome than everyone else.