VLP

Did you ever struggle to project a video on your second screen during a seminar or a church service?
There is nothing like having to drag a window to the second screen and then trying to find the play button, volume or full screen button on the remote screen.
You can embed your videos in a PowerPoint presentations or another "presenter" program but here is a very simple (and free) solution.
Step 1: download and install VLC. Find it on videolan.org
Step 2: download VLP and extract it to a location of your choice,
for example in C:\Program Files (x86)\VideoLAN.

VLP stands for VideoLan Presenter. It looks like this:

The rest is pretty self-explanatory...
You can create a shortcut to VLP on your desktop and drag one or more videos to it and voilà!
Update (v1.3, October 2022): it now supports the drop of a shortcut (.lnk).

Have fun, and most of all, peace of mind with a sleek, lightweight and free solution.