Most Star Wars fans are at least peripherally aware of the Star Wars Holiday special, but almost no one has seen it because it was never released on home video. The special aired on November 17, 1978. Ever since then, everyone involved has been trying to forget about it, destroy it, or at least deny that they did it willingly. But today, dear readers, you'll get a taste of how bad it really was.
(Plot note: the special revolves around a holiday called "Life Day" which is a sort of intergalactic version of Thanksgiving; Wikipedia has a full plot description, including the unforgettable line: "When the cartoon finishes, Lumpy works to create a translation device from his Amorphian machine that will fool the Imperials into returning to their base by faking their commander's voice. To do so, he first must watch the manual for the device, being presented by a malfunctioning, incompetent robot (Harvey Korman again).")
If you like this, don't miss Wikipedia on the canonicity of the special.
Here's Your Daddy
In this clip, Han Solo and Chewie have saved the day (spoiler alert!). It is, as Merlin Mann pointed out, brutal. Lots of awkward hugging and unearned cross-species affection.
Happy Life Day
A bunch of moaning, groaning Wookiees wander around, then there's some more bizarre unearned "we're all family" stuff. And then Princess Leia sings a song! There is so, so much wrong with this on so many levels.
You'll Be Celebrating Life Day Before You Know It!
Apparently a collection of clips from the special including bits from the beginning; there's some sort of space battle, Wookiees are cooking and making strangled barking noises, there's a weird videophone thing and a music video...it's just a mess.
The Real Intro
This appears to be the uncut intro sequence, including a low-stakes space battle and an amazing set of credits. With special guest stars including, no kidding, Beatrice Arthur, Art Carney, and Jefferson Starship.
Boba Fett Cartoon
Wow, nine minutes of cartoon content. Huh? What does this have to do with Life Day? I really like the "Star Log" entries -- that's not a Trek ripoff at all!
THE WHOLE THING
Anthony Daniels (who played C-3PO) said that "you will die" if you watch this special. So, with that warning out of the way, here's the most complete version I could find online. You have been warned.
There's a gap in here; videos blocked by content owners. I'm guessing these segments also contained the deadliest material.