Is there a way to do Bokeh or defocus or anything of the sort in Blender's default render engine?
The "Depth of Field" tab under the render settings has the controls for the dof, but in order for anything to happen you need to also go to the compositor and add a "defocus" node, and be sure to plug not just the image into the image socket, but also the Z value into the Z socket, and make sure "Use Z Buffer" is enabled.. Then you can play around with the f-stop value in the node till you get a result you're happy with. Hope that helps!
You can change the object that will be the focus point, or you can input a distance instead. Change the value of F-Stops to achieve the Depth of Field/Blur effect you're going for.
As for Bokeh, tick the High-Quality box and you can change the number of blades to whatever bokeh effect you're trying to achieve.