Bokeh is a term that has become very popular in the photographic world. It is the way a lens renders out of focus points of light. It may be intimidating to some, but it is actually very simple to do. All we are doing here is shooting with a very shallow depth of field. First you need some points of light; Christmas lights are perfect for this. You then want to put your subject far from your background. The photograher needs to shoot close to the subject that is intended to be in focus. Turn the camera onto Aperture Priority and open up the aperture as wide as possible. From there it's then just a matter of how you want to compose the image against the light source.
Tamron 60mm f/2.0 @ 1/2 sec. - f/2.8 - ISO 100
It was mentioned that a wide aperture is best for good bokeh. However, this effect can be achieved with any lens....
Tamron 16-300mm VC PZD @ 135mm - 2 sec. - f/6.0 - ISO 100
Typically other photographers will say that you have to shoot with a fast prime such as a f/1.8 or f/2.8 lens, but the above image was shot with an all in one zoom at f/6.0. It was mentioned earlier that bokeh has to do with a shallow depth of field. It is critical to remember that our f-stop is not all that affects DOF. It is also the focal length and focus distance. To get the above effect, all that was needed was to zoom and change positioning.
Bokeh can be very rewarding when done correctly. As always, practice and experiment with it. But most of all, have fun!