The term 'Fresh Expression" is used to cover a wide range of activities. A 'pure' Fresh Expression would be something that has little if any apparent connection to an established church - such as a Cafe Church run in a coffee shop on the high street, or a 'spiritual' meeting in a room in a pub or community Hall. Other more obviously church related activities, such as a Messy Church or a Cafe Church on church premises, which are run as church outreach programmes also come under the fresh Expressions Umbrella.
The key thing is that they are primarily for folk outside the church, and are organised with their needs and understanding in mind.
The United Reformed Church is part of the Fresh Expressions Movement.