exoteric said:

I'll start out -

 

Tuple Syntax 
a la (precise parenthesization not so important here)

(1,2,3)

Tuple Enumeration

Not a language feature but allow tuple to be enumerated (IEnumerable<T>) for both homogeneous and heterogeneous tuples, meaning these two cases would both be legal

foreach (var x in (1,2,3))
  Console.WriteLine(x);
foreach (var x in (1,"WTF",3))
  Console.WriteLine(x);

Where in the first case the tuple would be IEnumerable<int> and in the second case the tuple would be either IEnumerable<IDynamic> or IEnumerable<Object>.

I'll agree with tuple syntax, but the (1, 2, 3) stuff isn't the important part. What's much more important is tuple assignment.

 

int a, b, c;

(a, b, c) = TupleReturningMethod();