When Samantha is sitting at the foot of the bed with an ice pack on her head, eating toothpaste, in one shot she spits some toothpaste out and it goes over Chris' hand. In the next shot his hand is clean.
(This is actualy a cool coincidence.) In the credits the song "Forgiveness" plays, but sometimes in the song you hear three Beatles effects, like the way she says "Time, time, time" 6 times and ends with a cat noise. That is kind of like in the middle of "Hey Jude" where instead of "Time" the word is "Better" and they end with a scream. And after the cat noise, you hear a "Ha Ha Ha" like the song "I am The Walrus," and at the very end there is a build-up of orchestra followed by an ending note that holds to fade like the song "A Day in the Life."