<?php

$text = '{test|test2|test3} some other stuff {some1|some2|some3}';

$parser = new Parser($text);
$parser->parse();
for($i=0;$i<4;$i++)
    echo $parser->replace().'<br />';

class Parser
{
    private $vars;
    private $text;

    public function __construct($text)
    {
        $this->text = $text;
        $this->vars = array();
    }

    public function parse()
    {
        $pattern = '/\{([^}]+)\}/';
        $matches = array();
        preg_match_all($pattern, $this->text, $matches);

        $matches = array_shift($matches);

        foreach($matches as $match)
        {
            $this->vars[$match]= explode('|', str_replace(array('{', '}'), '', $match));
        }

    }

    public function replace()
    {
        $text = $this->text;
        foreach($this->vars as $k => $v)
        {
            $rand = rand(0, count($v)-1);
            $text = str_replace($k, $v[$rand], $text);
        }

        return $text;
    }

}