I want to serve a 3 day notice to my tentent for non payment of rent. Is there a law not to serve this paper on a Sunday?

Sundays and holidays do not count. You must do this on Monday to make it legal.

Generally the 3 days have to be business days, but that doesn't mean you can't serve them on a weekend or holiday.

True, you can serve them anytime or day you wish, but most people don't understand the Sundays and holidays don't count as far as just when the actual 3 days are up. The reason I said Sundays and holidays don't count is if you serve your tenant on a Sunday, they will be under the impression that they have until Tuesday when in fact they have until Wednesday to do something.

Umm, if they are late, who cares if they misunderstand

I agree with Scott, they can come on here and ask if Sunday counts if they misunderstand, their ability to understand is not your issue, don't worry about what they think, You serve them and make them pay or evict them.