Recent advances in femtosecond laser technology made possible generation of laser pulses consisting of less than two optical cycles with stabilized "absolute" phase. This talk will present recent results of strong-field photoionization experiments. Several novel effects were discovered in the respective photoelectron spectra. On the one hand, these can be used for a precise determination of the absolute phase. On the other hand, the experiments can also be regarded as a new kind of coherent control. Further, the data provide insight into the mechanisms of strong-field ionization on the sub-cycle time scale.