I just booked myself a trip to Cuba with miles. One direction I am flying on a single award from the United States to Cuba. On the return, I am flying two awards: Cuba to Colombia and Colombia to the United States.

I used American Airlines, Asiana, and Lufthansa miles, all of which are easily available to Americans.
Can Americans Travel to Cuba?
Here is the State Department's page on visiting Cuba.

I am going to travel to Cuba on a general license as a journalist.