I'll post how I made it but truthfully this can be made many different ways. I've made this without corn syrup for example and just used more marshmallows. So don't be afraid to experiment!
Rice crispy squaresMelt in a large pot:
4 cups marshmallows
1/4 cup margarine
1 cup corn syrup
1 tsp vanilla
Remove from heat and stir in:
8 cups rice crispy's. Blend well then gently stir in:
2 cups chocolate chips
Press into two 9x13 pans and chill in fridge before serving. Enjoy!