Professor Volokh posted a question that he is giving to his Criminal Law class:

Bert and Ernie are walking down the street from the local bar, when they see their old nemesis the Count. Drunk and a little paranoid, they conclude that the Count is trying to kill them, so they decide to kill him to prevent that from happening; but they don’t want to confront him directly.

Fortunately, they see Oscar sitting in his trashcan. "Help us out, Oscar," they say; "come up to the Count and ask him to count your trash bag collection." "No!," says Oscar, annoyed by the request. "You’d better do it, or else we’ll beat you up." "Okay," says Oscar, and does what they ask of him.

While the Count is distracted, Bert pulls out his handgun and pulls the trigger; but it turns out that Bert had forgotten to load the handgun. Bert and Ernie then run away, but Oscar isn’t as fast. The Count jumps on Oscar and tries to kill him by drinking his blood, but the police come before Oscar is entirely drained, and save Oscar’s life.

What crimes have been committed, or may have been committed, here? Apply the Model Penal Code as well as the various common-law rules that we’ve studied.

The comments to his post (many from top law professors around the country) are funny. 

But I think you can nail Bert and Ernie for conspiracy, and attempted murder (both through the conspiracy).  Their intoxication is not a defense.  The fact that they were supposedly acting in self-defense would not hold muster under a "reasonable person" standard (or even a "reasonable Muppet" standard).

The Count could be charged with voluntary manslaughter.  He may have a reasonable self-defense defense, albeit a mistaken one (thinking incorrectly that Oscar was trying to kill him).

Oscar would probably not be charged with anything, since, according to the facts he was not aware of the conspiracy.

Sadly, real life crimes are never as intellectually interesting as the ones made up by law professors.