Here are 20 fun newsletter ideas you can use to engage your audience:

1. "Today I Learned" Facts: Share a surprising fact or piece of trivia every day/week that your audience might not know.

2. DIY Projects: Offer simple and creative do-it-yourself project ideas, complete with step-by-step instructions and photos.

3. Quote of the Day: Share an inspiring or thought-provoking quote, along with a brief commentary or related story.

4. Behind-the-Scenes: Give your readers a peek behind the scenes of your business, creative process, or daily life.

5. "Reader of the Month": Highlight a reader each month, sharing their story, why they follow your newsletter, and any special achievements.

6. Book/Podcast/Show Recommendations: Curate a list of must-read books, must-listen podcasts, or must-watch shows.

7. Trivia Challenges: Include a fun trivia question in each newsletter and encourage readers to respond with their answers.

8. Pet of the Week: Feature a subscriber's pet each week, with a photo and a short description.

9. "Did You Know?" Series: Share little-known facts or historical tidbits related to your niche or industry.

10. Cooking Corner: Share a new recipe each week, along with cooking tips or a spotlight on a unique ingredient.

11. "Throwback Thursday" Stories: Share nostalgic stories, old photos, or interesting historical events each Thursday.

12. Creative Writing Prompts: Offer a weekly writing prompt to inspire your readers to write and share their creations.

13. Monthly Challenges: Propose a challenge for your readers to complete each month, such as a fitness challenge, a creative project, or a habit-forming exercise.

14. Life Hacks: Share useful life hacks, tips, and tricks to make your readers' lives easier.

15. "What’s Trending": Summarize current trends in your industry, pop culture, or on social media.

16. Subscriber Polls: Include a short poll in each newsletter to gather feedback, opinions, or just for fun.

17. Event Calendar: Highlight upcoming events, webinars, or virtual meetups that might interest your readers.

18. "Ask Me Anything" Feature: Allow subscribers to ask you questions, and feature your answers in the next newsletter.

19. "What’s in Your Bag?": Ask a reader or a guest contributor to share the contents of their bag, along with why they carry certain items.

20. Short Stories or Serialized Fiction: Share an original short story or a serialized piece of fiction, releasing a new installment with each newsletter.