Games You Don't Think About #8: getting the audience to join in

Toys
Your voice.
An audience.
(recommended: Words of persuasion)
(optional: other musical instruments)

Scoring:
The volume of the audience during the chorus (or repeated sections).

Restrictions/Rules:
none I can think of

Time to play:
2-12 minutes (basically, slightly more than the length of the song)

Tips/clarifications:
tip1 - if the audience sings a section that you DO NOT (maybe echoing a portion or maybe a chorus that you shut up for)
tip2 - it can help to quickly reinforce the idea of crowd participation before your song. Some people aren't sure if it's OK.

Good points
Pleasure of pleasing others.
Different audiences make for different play experiences.
Audience can give surprising responses, necessiating quick thinking.

Negatives
How well this goes can depend heavily upon audience. A room full of musicians is nearly always more eager to join in.

Games You Don't Think About #7: Licking a knife

Toys
A sharp knife, covered in some tasty residue (e.g. tomoatoey bits).
Your tongue.

Winning Condition:
The blade appears clean and your tongue is not cut.

Restrictions/Rules:
Only your tongue

Time to play:
20 seconds

Tips/clarifications:
I recommend licking at a slight angle, to avoid accidents.

Good points
A feeling of slight rebellion.
Tasty goodness!
A slight feeling of danger.

Negatives
Chance of injury.
Soon becomes easy.