One of the nicest things you can do is leave the dead bird in the kitchen and just have a plate of meat on the table. Also, leave the gelatin out of your cranberry sauce and the marshmallows off the sweet potato casserole. Flavor your green beans with Liquid Smoke instead of ham. Use cream of mushroom/broccoli/asparagus for your casseroles and dressing/stuffing instead of cream of chicken. You won’t miss the chicken; I promise.
If you’re wanting to go a step further, a Tofurky is nice, but isn’t necessary. I actually like the Tofurky roast, but I’m just as happy with macaroni-and-cheese as my entrée. I’m not a vegan, though (I eat dairy, eggs, and honey, so I'm just a standard vegetarian). If you want a nice entrée that’s vegan, I humbly recommend this pumpkin risotto. At the end of that post, I also include links to a variety of other veg*n options for entrees and side dishes. But if you just really want your vegan friend to have a turkey of some sort on their plate, there’s always the option to make a turkey from fruit. That's pretty darn cute.
All that said, you don’t really have to do anything special. We’ll be fine, really. However, a little effort may preclude any mention of PETA and the recent allegations of cruelty at Butterball turkey farms. I’m just sayin’.