Just tried the "vegetarian special sandwich" at the Sabra Grill (next to the Eliot Street Cafe, which is on the corner of JFK and Eliot near Harvard Square) following the advice of Emma F (see her post linked below).
It's a pita roll-up spread with hummus (as far as I can tell from the sandwich, fairly galicy hummus), grilled onions, eggplant, zucchini, peppers and a liberal dollop of garlic paste, all rolled up and toasted on the grill. Very tasty! Probably would have been even better if I ate it fresh and crispy off of the grill and not take out, by which time it was getting a bit soggy. They leave both ends of the roll open, but have a clever way of wrapping with paper and foil that I haven't seen before, so it's not messy to eat and avoids those extra thick and boring pita folds you find in most place's sandwiches. About $4.80, I think, and very filling.
Haven't tried anything else. The menu has all the obvious Middle Eastern sandwiches and plates, but not much else. It's a small hole-in-the-wall (but clean) with only about 12 seats. The owner is always there and is very friendly. I still haven't tried Sepal, but I'm moving Sabra to my favorite Middle Eastern sandwich shop based on just this one item. Hopefully their falafel sandwich is as good.
No sabra on the menu, however!