Blink and you'll miss it in the beginning of "The Mourning After" (1x10), as Bo and Kenzi talk to Dyson about the mystery of the week. Kenzi cracks a wildly inappropriate joke and Bo turns a slightly "I'm your big sister and I'm annoyed at you" look on her before it quickly turns into "Okay, that was funny".
Dyson: Had to pry it from her hands post-mortem. She cracked the shaft with her muscle spasms.
Kenzi: Ha. Shaft.
Kenzi in Dyson's body in "Original Skin".
For that matter, the serial killer in Lauren's body is pretty hilarious too. Zoie Palmer looks like she's having a ball.
After Bo is given amnesia and runs away from Kenzi:
Kenzi: What if Bo hitched a ride out of town and is dancing in a topless bar, despite rival girls trying to bring her down?
"Fae don't believe in divorce for the first thousand years. What? Is it okay to expect people to actually give it a shot!"
Also: Ryan versus Kenzie.
Vex forcing The Morrigan to dance half-naked.
Vex being the only one who apparently notices the UST between Kenzie and Hale.
Vex: Okay, seriously, am I the only one who can see this!?
In general, anything that comes out of Kenzi's mouth.
"I'm human remember? We drive SUVs and we drop sewage into pretty lakes and we will burn this planet to the ground if it means one more cheeseburger". Mind you it's only compounded by the fact that she's holding a chainsaw at the time.
Kenzi: He left her at the alter. For our other sister.
Two minutes later, at "book club" (drinking and gossiping).
Suburbian Lady: I always say if it's getting hard then something's going wrong. Kenzi: I always say the opposite, something's wrong if it's getting soft, am I right? Ladies: [gales of laughter] Kenzi: [to Bo] I'm good at book club!
Bo and Lauren getting their make-out on during "Let The Dark Times Roll". And the lucky butler who walks in on them.
Bo: Get. Out.
Lauren: But leave the tray.
And then The Morrigan walks in.
Morrigan: Lame! What's next, you gonna braid each others hair? Scissor already!
Bruce, the Sushi Table.
When Vex's severed hand is in a bowl of ice at the Dahl, the middle finger is sticking up. Plus, Vex's line after he injects Bo with Lauren's drug to block her powers:
"Well, didn't someone get box-blocked by their ex's pointy thing (gestures with his knife). Oh look at that, I made a funny.
Pretty much all of the interaction between Lauren and the Morrigan in "Of All the Gin Joints". Lauren revealing just how much of a Trekkie she is, the Morrigan's response (Oh honey, I obviously came just in time), Lauren later doing a Stardate Doctor's report, etc. Oh, and the name of the beer they're drinking? Dark Belch.
The Morrigan: I was going through a Redneck phase.
Many in "Destiny's Child", Bo prepares to open the jar risking being kidnapped again. Trick grabs a mop handle to use as a staff, Dyson wolfs out, Lauren readies as a syringe, Kenzi... grabs a fork.
Later Trick goes to see Wai Lin, but finds her sister Doa Ming instead.
Doa Ming: So sorry, but Lin is away. Helping out with some very important international negotiations.
Trick: She's back at the U.N.?
Doa Ming: Facebook. (Trick raises an eyebrow) The world has changed, what can I say?
"Origins" Lauren mocking Evony after turning into a human was both awesome, and hysterical. Most notably, how she did it.
"Are you try to melt me? That's adorable."
From the same, dialogue from Vex implies that Shakespeare is a Fae. And he still regrets the ending to Hamlet.