In AIML a random tag gives one of the elements at random.
<category>
<pattern>How are you?</pattern>
<template>
<random>
<li>I'm okay.</li>
<li>I am great!</li>
<li>Not so good.</li>
<random>
</template>
</category>
Bot Libre also lets you add multiple responses to a question and chooses one automatically.
How are you?
I'm okay.
I am great!
Not so good.
Self also has a random() function.
How are you?
Template("{random ("I'm okay.", "I am great!", "Not so good.")}")
