In the final episode, whilst trying to find Marsha, Daisy sees Colin the dog wandering through a hole in the fence. She tells the other characters, leading to the following exchange.
Tim: Daisy, let's go! Daisy: What about Colin? Tim:[impatiently] Sod Colin! Daisy:[shocked] I'm not gonna sod Colin!
All the Star Wars stuff in "Change", but particularly...
Tim: Jar-Jar Binks makes the Ewoks look like fucking Shaft!
Everything in this list. Drowning Lara Croft; the male psyche's psychic connection when it comes to slow-motion gunfights; "butterfly with a bomb" (and also "I'm Andy McNab, I'm Andy McNab, I'm Andie MacDowell...")...
Bilbo throws down his comic and punches him in the face
Tim and Daisy's argument via the medium of Tekken.
"Is Jabba the princess?"
Perhaps the Crowning Moment of Funny in the entire series; When Tim, Daisy and Brian are watching Star Wars and are discussing how the fact that if the gunner in the first movie had destroyed the Pod C 3 PO and R 2 D 2 were in, then none of the movies would have happened
Brian: Chaos theory....
Brian: The predictability of random events. The notion that reality as we know it - past, present, future - is in fact a mathematically predictable preordained system.
Daisy: So somewhere out there in the vastness of the unknown is an... equation... for predicting the future?
Brian: An equation so complex as to utterly defy any possibility of comprehension by even the most brilliant human mind, but an equation nonetheless.
Mike fantasising a very gung-ho method of infiltrating the Dark Star Comics offices. Only lasts two seconds, but it's one of the best Matrix parodies ever... perhaps because it's so short.
I think what really helps is the utterly hilarious bog-eyed look Mike has once the fantasy cuts back to reality.
"I once punched a bloke out for saying that Hawk The Slayer was rubbish... (...) but that's not the point, Tim. The point is, I was defending the fantasy genre with terminal intensity, when what I should have said is 'Dad, you're right, but let's give Krull a try and we'll discuss it later.'"
Basically every scene Bill Bailey was in.
How about the time that Tim and Daisy talk about which Scooby-Doo characters they were when they were young?
Daisy: I was always Daphne when I was little. Who were you?
Tim: Freddie, obviously.
Daisy: Yeah. Now, look at us. [Slow pull back, revealing Tim and Daisy dressed exactly like Velma and Shaggy.]
Tim's line and reactions from outside the restaurant in the penultimate episode:
Tim: We've potentially destroyed her faith in the integrity of today's youth... [Everyone stares at Tim rather sceptically] ...Young Adults.
And the interview that inspires Daisy to create the play. The magazine editor starts rambling on and Daisy, due to being high, zones out and gets an opportunity to answer one question ("Would you consider yourself a post-feminist?"), which is rephrased ("Do you drink pints or shots?"). She completely cocks it up by adding a V-sign and saying "Girl Power!"
Daisy: I knew I should've bought Huge Fat Cocks.
A very quick moment:
Tim: Okay, now, listen. When we get there, let me do the talking, alright? I am the only one here that's capable of serious communication, so...sorry, sorry, that sounded bad, I didn't mean to suggest that you're not good communicators. Alright, Mike?
Brian sets up an installation with a telephone constantly ringing. He feels like there's something missing, whereupon he promptly knocks himself out cold with a paint tin. He wakes up hours later after the presentation is over and the gallery owner congratulates him for remaining lying there for the duration. When asked where he's going after, Brian says "Hospital" to which the gallery owner says, "Ah, one of Damien's trendy new bars."