Eric Feron, a Google AdWords Community Manager, posted on Saturday at the Google AdWords Help forums that a bug may have impacted your ads from displaying on Saturday.
In fact, it was not just any Saturday - it was one of the busiest and most successful Black Friday/ Cyber Monday weekends for online shopping ever. And it is possible that your Google AdWords ads were not showing because of a payment bug.
Eric from Google explained:
There is a technical issue affecting payment on some accounts causing ads to not show.
Engineers are working on resolving the issue as soon as possible.
It seems that the issue was addressed quickly but I am not sure how long it lasted. Was it a few minutes, hours, half the day? I am currently not sure.
It seems the issue started for some on Friday and some are still saying the issue is not resolved for them. I am not sure if this bug is related to those people or not.
Forum discussion at Google AdWords Help.