Spatial Curvature, Dark Energy Dynamics, Neither, or Both?

Observations over the two last decades have persuaded cosmologists that (as yet only indirectly detected) dark energy is by far the main component of the energy budget of the current universe. I review a few simple dark energy models and compare their predictions to observational data, to derive dark energy model-parameter constraints and to test consistency of different data sets. I conclude with a list of open cosmological questions.