Visible crew/equipment: When Grace is up against the wall pretending to be the ficus a red boom mic drops into shot.
Continuity mistake: When Jack lets slip about Will's affair with Steven to Grace, he throws a blue tassel to the floor, and bends over so Grace can kiss his butt. But when he stands up he puts a purple tassel back on the table. (00:28:15)
Alley Cats - S1-E21
Plot hole: In the bowling alley scene, Ellen states that Grace would need to knock down 27 pins in order to tie. Will and Grace then have a conversation, and Grace gets a strike with her next ball. They then start gloating that they have beaten Rob and Ellen, but the scores don't add up, and they couldn't go into the lead on that round.
Continuity mistake: As Grace and Campbell kiss on the couch, Will returns to the cabin and then Grace shuts Campbell outside. The edge of a rug with tassels is sometimes draped over the back of the couch in some shots, and isn't there in others. (00:15:25)
The Unsinkable Mommy Adler - S1-E13
Continuity mistake: In the restaurant scene, after Will grabs a breadstick and Grace snatches it from him, the position of the breadsticks in the bowl, in the centre of the table, constantly change through the whole scene. (00:33:50)
Where There's a Will There's No Way - S1-E7
Continuity mistake: Grace puts her chocolate donut down on her pad. It then vanishes, then reappears. (01:06:05)
Continuity mistake: After letting Campbell out, Grace pulls the white blind down the door, and it stops about halfway down the door, and gets stuck, and is still rolled at the bottom. In the very next shot, the white blind is now unrolled all the way down perfectly. (00:07:00)
The Truth About Will & Dogs - S1-E10
Continuity mistake: When Karen was at Will and Grace's flat with Jack babysitting the puppy. She puts her cocktail glass down on the table and leaves, but when Will and Grace come back from the movie there is no glass on the table. (00:36:50)
The Truth About Will & Dogs - S1-E10
Visible crew/equipment: Jack and Karen are sitting on the couch, and Grace says, "come on, let's go." There is a boom mic visible at the top of the screen, it rotates towards Grace. (00:14:38)
Continuity mistake: When Jack finds out that Grace doesn't know who Steven is, he picks up a blue tassel - twice between shots. (00:28:15)
Continuity mistake: When Grace sits on the sofa (before Jack enters) her black bag is on the table in front of her. When Jack enters, wearing the alien costume, the bag is suddenly on the floor. Then when Jack gets up to leave the bag has moved itself back onto the table. (00:22:20 - 00:23:40)
Will on Ice - S1-E11
Continuity mistake: When the gang are at Champions on Ice, Karen gets out a bottle of champagne and a glass a starts pouring herself a drink. As the shots change, the bottle and glass keep swapping hands, even as she is still pouring. (00:13:45)
Revealing mistake: When Grace and Will are looking at the large tin of Protein shake powder, you can see there is tape covering all of the logos and brand name on the tin. (00:21:45)
Answer: A history of the game can be found at http://www.fast-rewind.com/bacon.htm.
J I Cohen