"a penguin in flight, with cool sunglasses on"

The US military is so hard up for recruits these days that they're allowing new-wave penguins to enlist.

"The Notre-Dame de Reims under attack by space dinosaurs, being valiantly defended by a giant Woody Allen"

Being even the slightest bit confrontational like this is basically as valiant as Woody Allen gets, giant or otherwise.

"John Madden and Captain Planet hang out on a Sunday afternoon"

Don't quote me on this, but I believe they met through AA.

"Angry Cats Staring Down Clowns"

One theory is the one with the hat is hiding their squeaky toys in his pants, but it's hard to say with such a vague title. As I've said before, genius works of art that stand the test of time are open to many varying interpretations.

"Two dinosaurs shooting lasers out of their mouths, and a bear is riding one of the dinosaurs"

The one on the left is a brontosaurus or whatever, not just a stalk with a head... he's in the foreground and you can't see the rest of his body. I would draw trees and stuff to give perspective, but perspective is something people who took art classes can do, and I am not such a person.

"Ben and Kristine (Ben's tall, Kristine's really short)"

I sure hope the real-life Ben and Kristine like flowers.