Martin -- you could also add that "chastushki" often have a bawdy element! This, and their short structure, makes them comparable to limericks, even though they have a different poetic meter.

Metrically, chastushki are quite similar to such humorous quatrains as:

Lizzie Borden took an axe
And gave her mother forty whacks.
When she saw what she had done,
She gave her father forty-one.

or

Will fell down the elevator --
Wasn't found till six days later
Neighbors sniffed and said, "Gee whiz!
What a spoiled child Willy is!"

But thematically, chastushki are often closer to such limericks as:

A plumber whose name was McGee
Was plumbing a girl by the sea.
Said she, "Cease your plumbing --
I hear someone coming!"
Said the plumber, still plumbing, "It's me."

or

There once was a beautiful lass
Who possessed a remarkable ass
It was not round and pink,
As you probably think,
But was gray, had long ears, and ate grass!