Season 8, Episode 20: "The Millennium"

Well, I just got your invitation to the Newmannium party.

You just got it? Damn, the mail is slow.

You knew I was having a millennium party...

...but you just had to throw yours on the same day.

I have done nothing unethical.

You have to cancel it, because I've told everybody about my party.

Cancel? Think again, long shanks.

I started planning this in 1978.