I actually had a mistake turn into a very nice dessert because of something similar to this.
First, the idea:
Take the scraps, and combine it with some fresh whipped cream flavored with an appropriate liqueur or extract (try banana liqueur with a banana cake; amaretto with chocolate). Crumble the cake, and combine with the whipped cream. YOu want it to be a heavy paste-like consistency. Line a muffin pan with plastic wrap, fill individual muffin tins, and freeze for a few hours. Then unmold, top with ice cream, nuts, syrups, or any other toppings. Makes a light mousse-like dessert with an added touch.
How I found this was I working on an entreme, and I wanted to do a banana layer. Unfortuantely, my banana layer didn't cook properly (bad oven), so I basically had an edge of a cake layer. Well, I crumbled it up as above, froze it, and I used it on top of a brownie layer (with a peanut butter mousse as a stabilizer layer). I then frosted the whole thing with a ganache, and it turned out beautifully. It makes for a nice cake layer-like element that is much lighter. Just keep it refrigerated or frozen.