SpiritVNC is FLTK-based VNC viewer that allows to have many simultaneous
connections opened and allows to switch between them efficiently.

Besides regular VNC connections, SpiritVNC also supports VNC-through-SSH
for encryption and more secure connections.  Also supported are reverse
or "listening" VNC connections as well as an auto-scanning function that
displays one VNC viewer for a user-defined time, then automatically
displays the next connected viewer, and so-on.