We are planning on purchasing 1 month Supersaver pass that we will validate on July 1, 2008 as we travel from Amsterdam to Bacharach. On July 31, 2008 we will be taking the night train from Barcelona to Paris. Will we have to pay extra on our last trip since the pass will expire at midnight of our last trip.
Best to contact Rick's people, Eurail, or RailEurope for this rather esoteric point, but I would think yes, you'll have to pay from wherever you are at midnight to Paris the next morning.
I believe that passes allow you to continue as long as you got on the train before expiration. But this question is best answered in the Transportation forum. Repost there.