The Purple Onion is also a chain of long-hours eateries in the greater Birmingham, AL area. There are currently six locations. Some of them are 24-hour, and the rest have late hours. The food is relatively cheap mediterranean and middle-eastern fare.
The food, overall, is quite good. The veggies used in their wraps (gyros, falafel wraps, etc.) and sandwiches are not quite as fresh as one might like -- think school lunchroom sandwich fixings -- but the sauces, meats and other (i.e. falafel) are very tasty. Their french fries are pretty standard, and their sauteed mushrooms are a tangy, juicy, well-spiced alternative to the usual sides. Their hummus and tzatziki -- crucial for a middle-eastern eatery -- are not all that they could be. The hummus is less viscous than one might like; owing, I think, to too much reliance on tahini as an ingredient. The falafel is good in a wrap, but too dry and bready to satisfy on its own. Their mint iced tea is wonderfully refreshing, and it ought to be, because as often as not there in no non-mint iced tea available. Vegetarians can make do at the PO, but their choices are limited. Vegans will find it difficult to eat here.
Only half of the appeal of the PO is the food; the rest is constituted by the late hours and the atmosphere that conduces to hanging out at night with friends who are welcome whether or not they happen to be quite sober.