Mona: "I know it seems stupid, but I totally have talked to ghosts. Knowledgeable ones, as recently as this summer. Let's do this. Secrets of the universe."
Hanna: "This is weird and dumb and the opposite of what I'm into."
Mona: "Just do it! I am your only friend! Why are you challenging me?"
Hanna: "Fine. Ask the spirits if Sean is a virgin."
Mona: "Something we don't already know the answer to! Let's ask if Ali's ever coming back."
Hanna: "That's macabre in the extreme, mon amie."

Ouija Board: "A-L-I..."
Hanna: "I know, Ouija Board! That's what we're asking!"
Ouija Board: "A-H-E-M."
Hanna: "Sorry."
Ouija Board: "A-L-I... V-E!"

And how does it know? Oh, just because Alison is plainly standing outside the French doors onto the back patio, just chilling. Practically gives a little wave. NBD.

MARIN DAYTIME

Aria: "Um, I'm not even going to address the ghost part, but remember how Mona was already A by that time?"
Hanna: "Whatever. This evidence in a murder investigation is going in the trash. Just like Spencer would tell us to do."
Aria: "Okay, but who else would know that story? Just Mona, right? So she told A about it, at least..."
Hanna: "Yeah, I've done everything short of calling in a bomb threat to make sure they don't let me back in there."
Aria: "Then I shall go, Hanna. I shall go, and I shall be victorious."

A random flowerpot is hurled at the backdoor, and never mentioned again.

Hanna, verbatim: "...So I'm sleeping at your house tonight."
Aria, verbatim: "Yep."

SCHOOL

Spencer: "Hey, Jason. What's up?"
Jason: "Just jogging past this high school half-naked. As a former Peeping Tom, I like to just keep my hand in."
Spencer: "Hey, are you going totally nuts by how we embarrassed ourselves by contributing to justice?"
Jason: "Yeah, I feel really bad that our judicial system is based on laws."
Spencer: "Are your parents going fucking crazy for any reason having to do with me or my buds?"
Jason: "I don't know, man. Fuck those guys."
Spencer: "Yeah, for real. Oh, I met your ex this morning. Cece Drake? That bitch is insane. Why would you date a carbon copy of your sister? Also I think we are all in love with her."
Jason: "Oh man, that psycho's back in town? Great. I hope you're not solving fifty other mysteries this month, because she's a whole can of sexy worms right there. Anyways, peace."
Spencer: "But you didn't answer like one single..."
Jason: Has vanished.