"Hey 'puter" responses:
Hello sir, I've heated up your lobster thermidor in the microwave. I'm one step ahead of you Alfred.
You have a message from the Condiment King. It says 'Pbbbffftttt!'
Welcome home sir. FYI, Robin is trying on costumes in the Batcave again. He's doing some pirouettes in Batryshnikov.
Hello, sir. Alfred is on the 17th floor, caulking the tiles in the second bathroom of the fifth master bedroom.
Welcome home. sir. I have your rom coms queued up, sorted by decade.
I am at your service, Lego Batman sir.
How can I help you, Lego Batman?
All referencing the recent Lego Batman movie.
"Ok google" responses:
I think you've got the wrong assistant, <name>.
Very funny, <name>. I mean, not funny "ha-ha," but funny.
There may be others, but those are the ones given with a few minutes testing.