Recent hardware developments have made possible the construction of relatively inexpensive large interactive display surfaces (LIDS). We have built prototype systems with office whiteboard sized displays using off-the-shelf data projectors and pen digitising equipment. Our group is investigating the use of these prototype systems in a variety of situations, including: programming, teaching, and both local and remote meeting support. The challenge of this research is to provide a style of user interaction in which the computer is an unobtrusive support agent - offering assistance, recording and replaying data - but not distracting from the interaction between people using the system.