More language esoterica - falling through a switch statement

Not that I'm much of a comp-sci guy but, I do like my language esoterica... earlier I posted about repeating structures in C# and it got me thinking about other language features - many of which are shared between VB and C# such as short-circuit evaluation and such. One language feature which I thought was pretty cool that C# didn't implement was switch-case fall-through. I'll bet that was a tough one to leave out! Here's an example of using fall-through behaviour to convert a number of Days, Hours, Minutes, or Seconds toMilliseconds:

function ToMilliseconds( unit, interval ) 
{
    var  number = unit ;
    switch (interval.charAt(0))
    {
        case 'd': case 'D': 
            number *= 24 ; // days to hours
            // fall through! 
        case 'h': case 'H':
            number *= 60 ; // hours to minutes
            // fall through! 
        case 'm': case 'M':
            number *= 60 ; // minutes to seconds
            // fall through! 
        case 's': case 'S':
            number *= 1000 ; // seconds to milliseconds
            break ;
        default:
            // If we get to here then the interval parameter
            // didn't meet the d,h,m,s criteria.  Handle
            // the error.   
            alert(intervalMsg) ;
            return null ;
    }
    return number ;
}