See if you can do this:
Read each line aloud...

This is this cat
This is is cat
This is how cat
This is to cat
This is keep cat
This is a cat
This is moron cat
This is busy cat
This is for cat
This is forty cat
This is seconds cat

Oh you bastard.

Huh? I don't get it...

Took a double take to get that one. Don't want to spoil it for the other "morons"

I also don't get it. Could somebody explain??

Read it again. But this time, read just the third word of each line.

dammit, TMFT, you ruined it for the rest of us... also took me a double take to notice it...

Hah! 38 seconds.

Gah! Rat bastitches. I was set-up I tells ya! Set-up!

Took me like 20 seconds... Am I a special moron?

If you are, so'm I! hehe

14 seconds. Plus 2 more for seething rage. Nice one TMFT

I didn't get it until it was pointed out..... shit.

I got to the line with moron in it and twigged, nice one though.

Huh...I didn't get it until TMFT told me. I guess I'm special. Special as in having to wear a helmet 24/7.