My son loves Volcanoes and dinosaurs. What's better for a boy than a volcano cake that actually has smoke coming out?
I used a doll cake pan for the volcano and a regular cake pan for the bottom. I used some small dinosaur toys for decoration (and let the kids take them home)
At the top of the doll cake pan (Volcano pan) I cut out a hole big enough to put a small soup can in. After the can was in the cake, I decorated the cake. The soup can remained in the cake through out the party.
To get the smoke effect I used dry ice and water. I put the ice and water in a small tomato paste can. The tomato paste can was then slipped into the soup can. This way through out the party I could take the tomato paste can out of the soup can and add more dry ice and water. To remove the tomato paste can and put it back I used thongs.
The cake would smoke for about 15 minutes before I would need to add more dry ice and water. I did this twice while the kids were arriving to the party and again right before we cut the cake.
The boys at the party did not want me to cut the cake, they wanted to keep watching it "smoke". You know you have a hit when 6 & 7 year old boys would rather look at the cake than eat it!
Make sure to take the labels off the cans and wash the cans very well. Also, very IMPORTANT-- make sure you do NOT touch the dry ice with your bear hands.
The whole party was a dinosaur/volcano themed party. I bought clay and had all the kids make small volcanoes on paper plates, then we added baking powder and vinegar to each child's volcano and they loved seeing it "explode".
We also went outside and put Mentos into a Two litter bottle of soda and saw it shoot up in the sky. (I'm a single full time Dad, I'm sure Mom's would not want to do that!)