Teens still love balloons and love to make things out of balloons.
Get the “twist ballooon kit with mini pump” from oriental trading. It sucks blowing these up without a pump and the smaller balloons are junk. Also, the kit comes with a great little manual for making simple animals and shapes. This can be as involved as the participant wants to get. We get people who want to make snakes and people who want to make elaborate multi balloon shapes and animals.
Inspiration can be found anywhere, especially on the internet. There are sites and youtube videos that will help.