There are a lot of cool things you can do with miles. One of the coolest things I've thought up, and one which I am strongly contemplating booking, would turn 57.5k United miles and 10k Avios into:

A trip to a Pacific atoll to be determined, Guam, and Japan. Three places I've never been.
Fourteen hours on the famous Island Hopper route.
Flat bed business class for seven hours.

The center piece for this plan is the Island Hopper route, which I became obsessed with last week and read everything a google search could find.