Our "Lifetime" Service kicks off from about 5.45pm every Sunday, with coffee, cake, and good company - then the service itself runs from 6-7.15pm. We meet in the church, with the chairs arranged around tables. 
The format is informal, but with similar elements to most church services: we'll sing and pray together, and hear part of the Bible read and explained. Lifetime often includes some slightly more interactive elements, too: sometimes there will be an opportunity to discuss part of the evening's topic, or some more creative ways of praying or thinking through what we've looked at from the Bible.