The Idea Factory - The Stranded
This idea came to me in a dream, the second highest source of ideas for me. This just goes to show how messed up my subconsious is these days.
A space ship is exploring the cosmos, searching for new colony worlds and signs of other intelligent life. They discover a candidate colony world and send down an away team of twenty. The drop pod heads back up to the main ship, but just after it docks the ship heads off into FTL. No one on the planet knows why or what happened. They don't have supplies for a long term settlement and must work together to establish a colony. As they do, they explore the world, possibly find signs of an intelligent civilization that died off in the past.