10 tips to spice up your Sunday School class sessions - 

1. Create Interactive Lessons: Incorporate interactive activities like games, puzzles, and role-playing into your kids lessons. Interactive learning is more engaging and will help them understand complex biblical concepts better. By changing thing up they will keep excited and engaged.
2. Do Creative Storytelling: Share Bible stories in a captivating and creative way. Use props, visuals, or storytelling techniques to make the narratives come alive. Risk being a little silly! Don’t forget to see if you have members of your congregation with acting skill. They just need to be asked.
3. Add Music and Songs: Integrate music into your lessons. Teach children songs related to the lesson's theme, and consider playing Christian music that's suitable for their age group. Of course, action songs are still awesome!
4. Arts and Crafts: Plan craft activities that connect to the lesson. Children can create art or crafts that reinforce the biblical teachings they've learned. When they take them home it also lets parents know what you have been teaching.
5. Outdoor Activities: Take the class outside occasionally for lessons or activities. Jesus used nature to teach the disciples. Try nature walks, scavenger hunts, or outdoor games can provide a refreshing change of scenery.
6. Guest Speakers: Invite guest speakers from the community or church to share their stories or expertise on certain topics. Hearing from different voices can be inspiring and, if they are interesting topics it will create a sense of anticipation.
7. Use modern Technology: Incorporate age-appropriate technology like educational apps or multimedia presentations to make learning more interactive and relevant. That being said, don’t completely give up on the old flannel graph if it connects with the younger kids.
8. Group Discussions: Encourage group discussions where children can express their thoughts and questions about the lesson. This promotes critical thinking and peer learning. The key here is to spend time creating engaging questions.
9. Themed Lessons: Create themed lessons or series that cover specific topics or stories from the Bible. For example, focus on the parables of Jesus or the stories of heroes of faith.
10. Field Trips: Organize occasional field trips to places like a local church, a museum, or a community service project. Experiencing faith in action can be inspiring. Do an internet search in your area to find the Christian ministries in your locality.

PS – Do whatever you can to create a sense of surprise. Excitement and anticipation is vital.