xkcd #3232: Countdown Standard
Title text:
Anyone who is caught counting ‘three … two … one … zero … GO!’ will be punished with a lifetime of eating only ISO standard food samples.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3232/


The day of the week shouldn’t matter, it’s either the Sunday that is coming up next or the one exactly a week after it. “This Sunday” should be the upcoming one and “Next Sunday” should be the one after. Doesn’t matter if it’s this week, next week or in two weeks.