1. Introducing a new topic:
* "Apropos of our discussion on travel, have you ever been to the Amazon rainforest?"
* "Apropos of your upcoming birthday, I've been thinking about some fun party ideas."
2. Connecting a comment to a previous discussion:
* "Apropos of what you said about the weather, it's actually starting to clear up."
* "Apropos of the recent news about the economy, I think we should be cautious about our spending."
3. Emphasizing a connection:
* "Apropos of her love for animals, she volunteered at the local animal shelter."
* "Apropos of his passion for music, he decided to start a band with his friends."
4. Introducing a witty or ironic remark:
* "Apropos of nothing, I think I just saw a unicorn in the park!"
* "Apropos of the chaos in the kitchen, I'm thinking we might be better off ordering pizza."
Remember, "apropos of" is a formal phrase, so it's best used in written or spoken contexts where you want to sound more sophisticated or literary.