You say you can modify the file's contents, so I suggest converting it to JSON (and separating the date/time).

[{date: 2012/02/11, time: 10:00:00, title: EventStart, color: Red}, {date: 2012/02/11, time: 10:10:00, title: EventStop, color: Green}]

Then you can use getJSON to get/parse it.

jQuery.getJSON('schedule.txt',function(data){

    // data is an array of objects

    $.each(data, function(){

       console.log(this.title); // log each title

    });

});

From here, you can read the times and figure out which one is the latest. Something like this should work:

if(Date.now() <= Date.parse(this.date+' '+this.time))

So, putting it all together:

jQuery.getJSON('schedule.txt',function(data){

    var matchedSchedule = {};

    // data is an array of objects

    $.each(data, function(){

       if(Date.now() <= Date.parse(this.date+' '+this.time)){

          matchedSchedule = this;  // If time matches, set a variable to this object

          return false; // break the loop

       }

    });

    console.log(matchedSchedule.title);

    // to set a global variable, add it to `window`

    window.eventTitle = matchedSchedule.title;

});