Assuming that the money was already taxed, 3 billion would go to charity. I would do it in an interesting way: instead of donating 3 out of 4 right off the bat, I would let it collect interest in a bank (hear me out!), and after a five- or whatever-year period, I would take out the interest and donate that. I would then let that money build interest again, and I repeat the process.
The other billion is waaaay more than I need, so I would spend maybe half a billion on friends and family, and the rest on supporting myself the rest of my life.
I'm a simple person, I know, but if I had to spend it on something more creative, it would be for something too perverse to even mention on these forums.