WARNING: Click links at risk of own sanity
(EDITED TO ADD: They've now moved the whole archive into Shockwave Flash, which makes linking to specific comics impossible. You'll have to click on one of the links above, use their search thingy to go to "October 23, 1989", and then click "Next" through the following 6 days. -B)
Seriously. There isn't a punchline in the whole six-day arc.**
I advise my readers to brace themselves before clicking ... younger or more sensitive readers should consider skipping the strips entirely. They will alter your brain for life. This is red pill territory here, and when your compulsion to scrub your eyeballs subsides, you will forever after mourn the loss of the calm, predictable universe you thought you knew.
* Their archives don't seem to have any navigation functionality. Control-click (Mac users: command-click) on each of my links in turn to read the whole thing without lots of back-and-forthing.
** Astute readers may argue that this phenomenon is indistinguishable from Garfield's usual content. However, in this case it's deliberate!