Okay kiddo, so an ACM conference on recommender systems is like a big meeting where smart people get together to talk about how to give us better recommendations. You know how sometimes when you watch a movie or buy something online, the website suggests other things you might like? That's called a recommendation.
Well, the people at this conference are trying to figure out how to make those recommendations even more accurate and helpful. They might talk about things like using algorithms (fancy math formulas) to analyze our past behavior and predict what we'll like in the future. Or they might discuss ways to incorporate our personal preferences and feedback into the recommendation process, so it's not just based on what other people like.
They might also talk about the ethics and fairness of recommendations. For example, if a certain group of people are only seeing recommendations for a certain type of book or movie, that might not be fair. So they might look at ways to make sure everyone gets a variety of suggestions.
Overall, the point of the conference is to share ideas and research on how to make recommendation systems work better for all of us. And who knows, maybe one day we'll be able to get recommendations for things we didn't even know we wanted but end up loving!