Weekend in Northern France

[SammyW]

Heading to france with a couple of mates at the weekend for a birthday. Bit last minute i know, but we're driving over and don't won't to head too far away from Calais, maybe an hour or two tops. No real plans as to what we want to do really, any ideas on an interesting town? I wouldn't mind taking in some war related spots while we're there, but it's not essential!