It is still common to see that people take turns to do their presentations using the same projector cable in a meeting. However, AverLogic has a reference design which can solve this inconvenience now.
Wireless HDMI Presentation Switcher looks like a set of dongles with multiple transmitters and one receiver.
Transmitter dongles go with presenters’ NBs, and 1 receiver goes with projector (the projector should be ceiling mounted). As long as pressing the “Present Key” on one presenter’s dongle, the one can transmit his presentation files (ppt or pdf) or video to projector for display wirelessly.