I have tried to make these holiday invites as flexible as possible so you can use them in a variety of situations. Do be sure to be specific when writing them out for your guests. Are they invited for the day or just dinner? Let them know what time to arrive - and put an end time on too if you wish.
Make sure you send your invitations out in good time so that everyone can make arrangements. And let your guests know if (and how) they need to let you know if they can make it.
If you need to add extra directions, or to ask your guests to bring something along with them - then you could use the back of the invite. Just write a little 'PTO' on the front so they don't miss it.
"Thanksgiving dinners take eighteen hours to prepare. They are consumed in twelve minutes. Half-times take twelve minutes. This is not coincidence."