A good day trip from Strasbourg is Saverne, a very cute town 1 hour (by car), less by train (there is a direct one) west of Strabourg, in the North of the hilly Vosges. It has a slithly different flair than the rest of Alsace, charming architecture in the center, a castle, a canal (with very nice path along it for going for a walk, from the castle, if you walk west, you're rapidly out of the town in to hills and the forest), cute little shops for wine and food. And since you go around christmas, Saverne also has a chritmas market. althought the market is much smaller and less touristic than the one in strasbourg, it is much more authentic.