A fundamental question that is important for the understanding of plasma processes concerns charged particles and plasma interactions. For moving particles (test objects in a plasma flow), these include the formation of plasma wakes. The plasma flow provides not only a direct dragging influence, but is also responsible for the generation of associated collective plasma processes, and the plasma wake can strongly affect interactions between charged objects themselves and the plasma. An example is the interaction between dust particles in the plasma sheath, where ions flowing to the electrode form the ion wake behind negatively charged grains. Here, a number of phenomena starting from the well-known case of a negatively charged body moving in a plasma (or immersed in a plasma ion flow) are briefly discussed. Most emphasis is given to recent results including, in particular, an absorbing moving object and a classical object in a quantum plasma.