One project that I have always wanted to do, is a scrolling platformer.
Scratch that.
INFINITY scrolling platform.
Perfect.
What do I mean by infinity? Well, here is the concept. We have a start section, and then beyond that, the game randomly generates the next part from a number of pre-sets that attach to it, and any randomness to it. As it keeps on going, the game keeps looking at the last section it makes, and choosing a compatible pre-set to connect.
[Start] > [Pre-Set 1] > [Pre-Set 5] > [Pre-Set 7] > [Pre-Set 11] > [Pre-Set 1] > [Pre-Set 4] > etc.
It would be a pretty big project to take on. I would basically have to map every section and look at when it can be selected to be generated. Some sections could be unique to others and even be repeated several times, offering new randomness in each bit.
Hopefully, you understood what I meant in this.
TL:DR - Randomly generating platformer. Pre-set made sections. Plenty of random.