Me and my friend Giulio randomly invite people we don't know to a dinner with us in one of our flats in London. We cook Italian, and we all share the bill for the dinner. There is no need to speak Italian to participate... but we can teach you some words if you want ;)
After dinner it's time to party! Bring you own booze; and every other pleasure you enjoy.
Nice and safe environment to meet random unknown people and to go past your comfort zone.