The Renormalisation Group tells us that, quite generically, quantum and classical many-body systems exhibit interesting scaling behaviour near critical points. Quantum critical points form a subset of these, corresponding to zero-temperature phase transitions. In the last decade, the AdS/CFT correspondence between conformal field theories on one side and string or M-Theory on the other side has developed into a rich and exciting subject. Until recently the applications of this 'duality' were mostly focused on theories relevant to model quantum field theories that are considered interesting from the point of view of high-energy particle physics - the prime example being N=4 SYM in d=4. In this talk I will describe how similar methods can be fruitfully applied to the theory of quantum critical phenomena in 2+1 dimensions. These systems are of practical interest, as it has been proposed that a quantum critical point underlies the strange behaviour of high-TC superconductors falling into the copper-oxide group.