Recently we have monitored the absorption line profile variations of a number of rapidly rotating B stars. These variations are observed as alternating quasi-absorption and -emission bumps that travel blue-to-red across the profile with a local period defined by the time to move one bump spacing. This type of pattern can be modelled successfully by assuming the presence of one or two active nonradial pulsation (NRP) modes in the photosphere of the star. Many observations show significant departures from the simple expectations of the models: successive bumps can have different amplitudes (which may vary on timescales of hours), and individual bumps can occasionally appear just ahead or behind the position predicted from a mean period. Nevertheless, we believe these anomalies can be treated as perturbations from a time-averaged pulsation model.