Echoing out a random variable

Place them into an array and choose from it randomly with rand(). The numeric bounds passed to rand() are zero for the lower, as the first element in the array, and one less than the number of elements in the array.

$array = array($first, $second, $third);
echo $array[rand(0, count($array) - 1)];

Example:

$first = 'first';
$second = 'apple';
$third = 'pear';

$array = array($first, $second, $third);
for ($i=0; $i<5; $i++) {
    echo $array[rand(0, count($array) - 1)] . "\n";
}

// Outputs:
pear
apple
apple
first
apple

Or much more simply, by calling array_rand($array) and passing the result back as an array key:

// Choose a random key and write its value from the array
echo $array[array_rand($array)];

Use an array:

$words = array('Hello', 'Evening', 'Goodnight!');

echo $words[rand(0, count($words)-1)];

Why not use array_rand() for this:

$values = array('first', 'apple', 'pear');
echo $values[array_rand($values)];