We were having a great time at the party until Jim puked all over the floor. That was a major buzzkill.

I was jerking off and then my dad walked in, god what a buzzkill.

Lois had a particular skill as a mother. When any of her children came home, faces beaming, eyes aglow with a report of good behavior at school, having caught a large fish or having really righteously beaten up the nerdy kid next door, she'd have just the right buzzkill to bring them back to reality. Later in life, she wondered why the kids never called, but only infrequently--she was not of an introspective nature, by and large.

A)

The protagonist experienced the ultimate buzz kill in "The Crying Game" when Dil removed -his- pants.

"Dude, I'm so high right now"
"yeah, but we just smoked the last of the weed and your girlfriend took our rent money to fix the dent you left in her car last week"
"Dude, could you be any *more* of a buzz kill right now ?"

B)

Urban Dictionary's inability to recognize identical terms with minor spelling variations is such a buzz kill.

It was such a buzz-kill when she barged in like that.

We where having a good time at the barbecue until Tonisha told everyone how she had three abortions. What a major buzzkill. Everyone went home soon afterward.

Person 1: Man we should egg that house
Person 2: No man we could get caught, I wanna go home
Person 1: Will you stop being a fucking buzzkill

The cops busted the party. It was a complete buzz kill.

"Zeke's girlfriend, Becky, was such a buzz kill."

It rained during the volleyball tournament. Kind of a buzz kill...