If you need to refresh your memory of the Star Wars saga ahead of The Force Awakens (or somehow have never seen them in the first place) you could watch them all one after another. That would take about 13 hours.
Alternatively, there’s this extremely abridged version from Eclectic Method.
Yup. Even at just 1 minute 45 seconds long, the prequels are still unbearable.
Star Wars: The Force Awakens if released December 17th in the UK