So this is a family favorite and I'm sure we may do slight things differently, but I realize it's not on here, so I'm typing the basic idea up. You play with portions, because it's a sandwich and isn't picky when it comes to that.
Lamb (I use pork semi-thawed so I can slice into super thin strips before it gets too difficult to do that)
colorful peppers, chopped
onions, chopped (white, purple, green, w/e your preference)
English Cumcumbers (or the cheap kind, but those you for sure have to peel first)
plain yourt and/or sour cream (I do hald and half)
greek seasoning (we use the yellow cylinder and it's a great meat flavoring for other things, so you'll use it. Or you can try homemade if you want--I haven't yet)
1. Slice up meat and cook it in some oil with lots of greek seasoning, until done.
2. Make Tzatziki Sauce: Cut cumcumbers in half and deseed. Then shred and squeeze out excess water. Add salt and let sit for at least a half hour to keep getting the excess water out. Frequently squeeze and drain. Then add sour cream/yogurt and a dash of garlic powder. I usually do about 2 cups with about 1 cucumber per cup (so 2 total). But more or less if fine. Add a dash or olive oil if desired.
3. Cut up other veggies and place them in seperate bowls so people can compile their own sandwiches as desired.
4. Warm up pita pockets right before stuffing. My mom puts a little oil in a pan and warms them up in it with some extra greek seasoning--heavenly, but a little more work if you're up to it.
5. Stuff to heart's content. Typically meat first, then veggies, then tzatziki sauce--plenty (that makes it!).
Typical Greek Flavors: oregano, mint, thyme, basil, marjoram, onion, garlic
see post of ethnic flavors: http://2nourishyourbody.blogspot.com/2010/11/list-of-ethnic-flavors-which-herbs-are.html