I have made a couple of different varieties. I made a banana split cake once with layers of ice cream, fruit, toppings, and topped with bananas. I used a layer of cake for the foundation and then built my way up with strawberry, pineapple, chocolate, in between layers of vanilla ice cream. It was pretty good.
I've also made the pie style with cookie crust and ice cream for filling. Other times, I've tried taking that a bit further. I used crumbled cookies for the foundation, then mixed some cookies with ice cream for a cookies and cream flavor, then alternated layers of the cookies and the cookie ice cream. I "frosted" it with Cool Whip and decorated it. It looked like a layer cake, but no actual cake was involved.