Half of Thanksgiving is having good snacks around while everyone waits to eat at 3:00.
We do stuffed mushroom caps for hors d'oeuvres sometimes. Buy some big crimini mushrooms (which are actually baby portabellos) and cut off the stems. Don't try to wash them. Mix up some bulk sausage with shaved parmesan, garlic, pine nuts, spinach, whatever - maybe a little egg to hold it together if you don't use parmesan. Then form a mound on each mushroom cap and cook at 400 for 20 minutes or so.
You could make a kick ass antipasto platter - with different kinds of salamis, olives, pickled veggies and provalone.