I will discuss some recent work on collisions of pointlike particles (conical singularities) in three-dimensional anti-de Sitter space. I will explain how to construct exact solutions corresponding to an arbitrary number of particles colliding in the centre of AdS to form either a new particle or a black hole, which is in general a non-trivial generalization of the well known case with two particles. I will also discuss taking the limit of an infinite number of particles, resulting in novel solutions consisting of a thin shell of matter collapsing to form a black hole. These solutions are new since they are the first examples of thin shell spacetimes that break rotational symmetry, generalizing the well known rotationally symmetric thin shell AdS3-Vaidya spacetimes. Some implications for the AdS/CFT correspondence will also be discussed.