Let's do this honky

Let us do the task before us in an awesome way.

"Hey, Double Danger, the President needs us to stop that nuclear missile from hitting the moon."

"Let's do this honky!"

Let’s go brandon

A phrase men who like to get pegged say to signal to others such a preference

Man: “LET’S GO BRANDON”
Woman: “wow, I didn’t know you liked getting pegged“
Man: “yeah, it’s my favorite”

Let the dogs out

To become overly intoxicated to the point where you just run around wild.

Aaron: What should we do tonight?
Jon: I don't know you want to let the dogs out?
Aaron: I'm down!

Let the battles begin

Smash fans and Final Fantasy fans alike have heard this song way too much.

I don't think this needs an example. Just let the battles begin

let's ft boo

Let's not

You : Let's FT boo

Her: let's not :)

Let the Zoo Out

Present Participle: Letting the zoo out
When you break up with a girl and she goes ape shit on you for breaking up with her.

I was dating this girl and now I like her best friend's friend, I had to let the zoo out.

Let the turtles free

When you need to go poo!

Denise: It's kind of like right now. I have to go let the turtles free. (Runs to the bathroom)