In Israel (i know we're not in europe but i thought this is an interesting discussion):
very popular on holidays and in the summer. from approximately passover, thru independence day, summer, then high holidays (in sept/oct). in your backyard, on your balcony , in every public park, beach etc.
foods served are usually: tons of chicken hot dogs, chicken wings, kebab or hamburger, skewers of meat/chicken/turkey with veg, chicken breast and/or boneless/skinless chicken thighs. sometimes steak but that is less common. marinades are usually meditarranean (olive oil, herbs, garlic, lemon) or sweet chili, or sometimes "chinese" or thai
many people will also roast veg at the same time - eggplant (usually roasted whole, then cut open and pour tahini sauce over), onion, tomato, mushroom, etc
sides: pickles, olives, hummus, fresh chopped tomato/cucumber. sometimes more salads. and of course pita.