Rounding to Halves?

Can anyone think of a good way to do this? I'm struggling.

I'm trying to write a function that will round a number to an integer or .5 for example:

3.2342 would round to 3.0

3.3453 would round to 3.5

3.6345 would round to 3.5

3.7666 would round to 4.0

you know what I mean? :p

This is the best way I can think of doing it.

PHP Code:

---

<?php
    function round_half($num)
    {
        $frac = $num - ( (int) $num);

        if ($frac >= 0.75) {
            return ((int)$num) + 1;
        } else if ($frac >= 0.25) {
            return ((int)$num) + 0.5;
        } else {
            return (int) $num;
        }
    }
?>

---