I just spent an hour constructing a class called Morse such that this outputs "HELLO WORLD!":

    Morse m;
    cout << (++++m) << (+m) << (+-++m) << (+-++m) << (---m) << ", "
         << (+--m) << (---m) << (+-+m) << (+-++m) << (-++m) << "!\n";

Damn you, C++! Why won't you let me overload the . operator? ;-)