Which one is correct?
- Our topic for today is games.
- Our topic for today is about games.
Which one is correct?
- Our topic for today is games.
- Our topic for today is about games.
Definitely the first one.
If you write it like this, it will be much clearer:
Our topic, for today, is, "Games."
It's because you had used the word "topic" and so the reader is expecting you to not only to describe the topic ("about games"), but to actually name the topic ("Games").
Meanwhile, if you had written:
Our discussion, for today, is about games.
Then, I would definitely see an argument for including "about."
Your topic is something, because topic means "a subject of conversation or discussion". Your discussion, lesson, book, etc. is about something because that is what its topic is. As you can see in Google Ngrams, in books, "topic is the" is far more common than "topic is about the".