There but for the Grace of Grace - S2-E21
Continuity mistake: When Ben is mixing the salad with Karen, Karen walks away, and one of the wooden spoons they were mixing with falls onto the worktop. In a following shot the spoon has suddenly jumped back into the bowl so that there are two in the bowl, then in a later shot the spoon vanishes once again. (00:54:25)
There but for the Grace of Grace - S2-E21
Continuity mistake: When Shannon is asking Grace why she didn't go through with her marriage, there are three glasses of near-empty wine on the table. In one shot they all completely vanish, then reappear in the next shot. (00:55:40)
There but for the Grace of Grace - S2-E21
Continuity mistake: When Will and Grace are sitting at the dining table discussing how much like Sharon and Joseph they are, the napkins on the table change shape and move around a bit, and one ends up with a plate underneath it just before Will picks it up.
Answer: A history of the game can be found at http://www.fast-rewind.com/bacon.htm.
J I Cohen