Games to play on a train?

"No, I will not play it on a plane,
And I will not play it on a train . . ."

Sorry, I had a bit of a Dr. Seuss moment while I was thinking of a title for this post :-).

The whole "fam damily" is going on a trip this coming Tuesday, which starts with a 15-hour train ride to Florida. The batteries for our various electronic devices (laptop, Nintendo DS, smartphones) won't last that long. I'm on the hunt for other free, compact entertainment options. I'm packing my knitting, a copy of Ghoulash, and several copies of Games magazine. Now I'm searching for either simple free print-and-play games or rules to games that can be played with standard playing cards. Anyone have any suggestions?