  We study higher order convexity properties of random point sets in the unit
square. Given $n$ uniform i.i.d random points, we derive asymptotic estimates
for the maximal number of them which are in $k$-monotone position, subject to
mild boundary conditions. Besides determining the order of magnitude of the
expectation, we also prove strong concentration estimates. We provide a general
framework that includes the previously studied cases of $k=1$ (longest
increasing sequences) and $k=2$ (longest convex chains).
