Ideas to improve Investment Club?

I run an investment club with about 20 members at my small high school with my friend and classmate. We have a really great teacher advisor who used to work in the investment field. He teaches great lessons and does fun investment games and such. However, he frequently has meetings during the period when we hold the club. I have been able to keep up, but I feel as though it is becoming boring and repetitive, and want to shake things up. I’m just looking for some fun ideas of activities to do when our advisor cannot make it. Thanks in advance!