Most of these are fun moments I've discovered over time that inexplicably haven't been used in specials. Just as a general thing, including the slates would be appreciated.
Daytime* October 22, 1982: I'll echo what was said before -- the end segment of Susan Stafford's last day.
* June 16-20, 1986: Anything from the week Susan returned.
* Something from October 3, 1986 (it being the 3,000th episode and all).
* Assuming it was shown during that week (and assuming it ever existed), the Pat & Vanna music video that he promoted on December 22, 1986.
* November 30, 1987 (Dave/Diana/Susan): After Round 3, Pat holds the Jackpot wedge upside-down and calls it the Topkcaj.
* June 14, 1988 (#3,421): Betty White makes an appearance.
Nighttime* August 29-September 2, 1983:
Anything from the week taped at the Ohio State Fair.
* January 1984 (Lloyd/Linda/Debbie): During the closing chat, Vanna spins the Wheel for the first known time.
* January 17, 1985 (Cynthia/John/Susie): During his interview, John pulls out a list of people he wants to say hello to. After he wins the game, Pat lets him begin reading said list into the commercial break...and after the break, John finishes reading the list and puts it away.
* February? 1985 (Milt/Fran/Stuart): After Round 3, Pat suggests that Milt put his remaining $179 on a gift certificate due to it being R3, to which Milt asks "Will we have time for a fourth round?" He opts to put his $179 on account if there's time for Round 4, after which Jack begins reading the prize plugs. Returning from break, Pat says "Welcome back to
On Account Playhouse." before doing the Final Spin.
* May 5, 1986 (#S-551, Ken/John/Andra): The
real outcome of the AT MY WIT'S END bonus puzzle.
* January-March 1988 (Marj/Paula/Denia): Before Round 4, Pat says "And now Vanna will...show you her hyphen." The censors were asleep that day.
* March 24-May 6, 1988 (Gerri/Maria/Kevin): Vanna gets her dress soaked during the closing chat...and it becomes transparent.
* January 2-February 10, 1989 (don't know the names): Joy goes for the His-and-Hers cars in the Bonus Round, but wants the one marked "His". After she wins, Pat moves the signs...and she finds a Free Spin on the car seat.
* February-March? 1989 (Michelle/Bettye/Andy): Andy. Just pick something.
* March-June 1989 (Maxie/Penny/Steve): During the final segment, footage is shown of the staff doing a "goofy hat" contest.
* Late April or early May 1989 (don't know the names): THE ACROPOLIS is a bonus puzzle. The contestant gets the second word, but fails to get the first.
* September 21, 1989 (#S-1184: Jim/Kim/Jill): During the final segment, Pat and Vanna guess how many lights are in the $25,000 sign; Pat then asks stage manager Randy Berke for the actual number (1,206), after which Pat asks for the sign to stop flashing (it does) and notes several burnt-out lights...at which point the entire sign turns off for a few seconds.
* May 6, 1992 (#S-1728, Sherry/Nancy/Scott): None of the players know what THE SOUL OF WIT (Clue) is. "What is brevity?" "Neil Brevity, he works in Vegas a lot."
* 1993: Nobody, including Pat, knows what is meant by the Clue puzzle SILENT BUTLER'S TARGETS and its answer of "crumbs or ashes". (This was on the 25th-Anniversary minisite, but never put on the main one.)
* January 1994: Raymond Taylor and any of his weirdness.
* 1994-95 (Season 12): I wouldn't mind a montage of every Pat joke regarding Megaword.
* March 1, 1995 (#S-2263): Renae's "Being on
Wheel of Fortune is a BOMBASTIC experience." and the subsequent reactions.
* June 22, 1995 (#S-2339/Teen Week II, Day 4): Pat embarrasses himself and Friedman (who appears on-camera) during the closing chat.
* January 31, 1996 (#S-2443, Carolyn/Randy/Shawn): During the closing chat, Pat reads to Vanna the full version of a poem partially quoted earlier in the show (it's a great poem), then fuels the "He and Vanna are in a relationship" fires big-time.
* September 12, 1996 (#S-2544, Tim/David/Kim): Pat holds the upcoming Jackpot wedge upside-down during the closing chat and calls it the Topkcaj. (That's right, Pat did the joke for
both Jackpot wedges. Well, at least they have something in common.
)
* April 11, 2006 (Barb/Jason/Drexelle): Barb tries to solve the Prize Puzzle but gets tongue-tied saying "chimichangas", after which Pat throws to commercial before remembering it's a Prize Puzzle.
* April 29, 2013 (#S-5816, Erin/Joe/Laura): Following the "featured prize" plug, Pat pokes fun at Mayor Bloomberg's soda policy with his 32oz logo-censored soda cup.
* June 7, 2013 (#S-5845, John/David/Tony): A ventriloquist contestant uses Pat and Vanna as his dummies during the closing chat.
There was one 80s episode where a contestant's flipper hit Bankrupt, the slide whistle started to sound, and then it cut off when the flipper just barely clicked over to the next wedge.
The only instance I'm aware of is October-November 1984 (nighttime, Father Rob/Betty/Marla), where it happened to Marla in Round 3.
If you know the exact date or week (or remote), post a suggestion and we'll tweet it to the show! You should include the original air date (and episode number if you can), or week (date and/or theme) if the exact date isn't known, and/or remote if it wasn't at home base, describe the clip-worthy moment, and if possible, give when in the show it happened. This could be a great opportunity to see moments that don't exist online. 
We can pretty much guarantee those will be disregarded.
