The American Red Cross has Adult CPR/AED/First Aid classes where the classroom portion is only an hour. There's an online component that you have to do beforeha

The American Red Cross has Adult CPR/AED/First Aid classes where the classroom portion is only an hour. There's an online component that you have to do beforehand, so the whole class is probably closer to 4 hours, but I think if you took only the classroom part you'd come out with a decent idea of how to perform CPR.