What's a good, generic algorithm for collapsing a set of potentially-overlapping ranges?

Question

I have a method that gets a number of objects of this class

class Range
{
    public T Start;
    public T End;
}

In my case

Answer 1

static void Main(string[] args) {
    List> ranges = new List>() 
    {               
        new Range(3,9),
        new Range(1,5),
        new Range(11,15),
        new Range(12,14),
        new Range(13,20),
    };

    var orderedRanges = ranges.OrderBy(r => r.Start);
    var lastRange = new Range(orderedRanges.First().Start, orderedRanges.First().End);

    List> newranges = new List>();            
    newranges.Add(lastRange);

    foreach (var range in orderedRanges.Skip(1)) {
        if (range.Start >= lastRange.Start && range.Start <= lastRange.End && range.End > lastRange.End) {
            lastRange.End = range.End;
        }
        else if (range.Start > lastRange.End) {
            lastRange = new Range(range.Start, range.End);
            newranges.Add(lastRange);
        }
    }

    foreach (var r in newranges) {
        Console.WriteLine("{0}, {1}", r.Start, r.End);
    }
}

Something like this. Didn't verify that it works with all inputs.