I've tried to limit myself to my top 5, since I'm sure others will have more input to this and I want some fresh perspectives.

In no particular order, because I frankly don't know how I'd even begin to compare them to each other...

1) Undertaker vs. Yokozuna for the WWF Championship in a Casket Match, Royal Rumble '94.  While the match itself is horribly, OUTRAGEOUSLY bad, that alone isn't enough to merit inclusion on this list, oh no.  You see, after it takes Yokozuna and ten other men to lock Undertaker in the casket, and after green smoke starts seeping out of Undertaker's urn, and after smoke starts smoking on the way down the aisle...the 'Taker appears on the Titantron and gives the following deep warning:

"Be not proud, because the spirit of the Undertaker live within the souls of mankind, the eternal flame of life which cannot be extinguished, the origin of which cannot be explained. The answer lies in the everlasting spirit.  Soon all mankind will witness the rebirth of the Undertaker.  I will not rest in peace."

Oh, and just to top the whole thing off, the Undertaker (Marty Jannetty in a Undertaker costume, to be exact) appears from behind the video wall and starts levitating up to "heaven" (the ceiling).

2) The hatching of The Gobbledygooker, Survivor Series '90.  In the weeks prior to Survivor Series, a large egg was seen at all the WWF house shows and television tapings.  Most speculated that it was a debuting wrestler, or at worst a celebrity guest appearance for the Pay-Per-View.  Well, sure enough, the big egg did crack at the Series, to reveal...some guy (Hector Guerrero) in a big turkey suit.  He danced with Mean Gene Okerland for the next ten minutes to the complete apathy of the crowd.

3) Mae Young giving birth to a hand, RAW is WAR.  It was sometime in early 2000.  You see, Mae was OLD, and she was also Mark Henry's girlfriend.  How can you NOT make the the logical jump to her giving birth to a hand?!  Are you stupid or something?

4) The Shockmaster makes his WCW debut, Clash of the Champions XXIV The Shockmaster was really Fred Ottman, who was Tugboat and Typhoon in the WWF.  On a "Flair for the Gold" segment, Sting and Davey Boy Smith announced their Special Mystery Partner they would team with to take on Sid Vicious and Vader at Fall Brawl '93.  Ottman was supposed to break through a wall of the set and come barreling in.  One prob: He tripped over himself after exactly one step and fell right on his face.  Let me amend that--he fell right on his purple glittered Stormtrooper helmet, which promptly rolled right off his face.  Ole Anderson, having no idea what was going on, continued his voiceover while everyone on the set tried (unsuccessfully) to stop from quaking with laughter.  This gets funnier every time I see it.  The sad part is that in typical WCW form, they actually tried to push Shockmaster as a legitimate threat after this.  Come on, he FELL FLAT ON HIS FACE and you're trying to convince me he's a contender?

5) The Brian Pillman/Stone Cold Steve Austin gun angle, RAW is WAR.  This one isn't even funny.  Austin had turned on his former Hollywood Blondes partner, brutally attacking him and on this taping, following Pillman to his home.  Pillman retaliated by brandishing a loaded revolver (not really, of course, but that was the storyline) for self-defense.  The camera "lost transmission" for a few moments while the gun was allegedly fired, during which time the sidearm was supposedly wrenched away from Pillman.  This was in extremely poor taste and is one of the things the WWF doesn't like to talk about much.

(Oh my god, how could I have written this and not mentioned Great American Bash '91???)