An orthogonal representation of a graph G is an assignment of a unit vector x(v) in the d-dimensional Euclidean space Rd to every vertex v, so that for every two nonadjacent vertices u and v, the corresponding vectors x(u),x(v) are orthogonal. Let d(G) denote the minimum dimension d for which such a representation exists. This quantity and its analogs over other fields arise in the study of the Shannon capacity of G and in the investigation of additional problems in Information Theory. What is the typical value of d(G) for the binomial random graph G=G(n,0.5)? In recent work with Balla, Gishboliner, Mond and Mousset, we showed that the answer is Θ(n/logn). This settles a question of Knuth. I will discuss the background of the question and outline the proof.