Ok so one of my friends did this to a girl who he didn't really know and she said yes. Ok here are the steps.
1. Get some type of bowl put water in it
2. Print out a piece of paper saying "Now that we've broken the ice will you go to homecoming/prom with me?"
3. Freeze the water with the paper in it to a block of ice.
4. Go to school and find her in the morning so it doesn't melt or keep it in a teachers fridge
5. Tell her if she can break this for you
6. She smashes it and she there's a note and she reads it, and she says yes