*I am not Catholic*
Regarding the whole Thanksgiving thing, Thanksgiving is traditionally a SECULAR holiday. It does however, make sense to celebrate it in a sacred way... to an extent. I don't know how churches deal with it in general, but in the Grantville Ministirium(all the churches in Grantville. period) we have an inter-faith service that rotates from church-to-church every year... it's not as diverse as it sounds, though, since the area isn't. But it's cool.... and it's not very long or anything... PLUS the sermon/homily/talk-thing was begun with a little history lesson this year.....
Thanksgiving was declared a National Holiday by George Washington during his presidency. He set it for November 28th. However, no one listened to him.... at least not in the long run. It was re-declared a National Holiday by good ole Abe Lincoln after a bit of prodding from Sarah Hale(I know this 'cuz I played her in a play).. Her name might sound familiar... she wrote the poem "Mary Had a Little Lamb." Anyway, Lincoln set the holiday for the THIRD THURSDAY of NOVEMBER... and save a few years during war-times... it's been celebrated ever since.