unique Value from the object collection

You can try it this way, but I'm not entirely sure what the outcome will be since you're evidently comparing two separate properties withiong the object in the collection.

var list = (from item in collection
            select item.).Distinct();

Of course, you can always implement a comparare class to pass to the Distinct() method that will handle the comparison in a more specific anner.

public class MyObjectComparer : IEqualityComparer<myobject>
{
    public bool Equals(MyObject x, MyObject y)
    {
        bool equals = false;
        if (x != null && y != null)
        {
            equals = (x.Month == y.Month && x.Day == y.Day);
        }
        return equals;
    }
}

   ...
   MyObjectComparer comparer = new MyObjectComparer();
   var list = (from item in collection
               select item.).Distinct(comparer);

The code above is in C# but you shouldn't have any problems converting it to VB.