In the generic case of any Flash media, there is not a general way of buffering it completely. However, standard Flash "media player" type apps just treat Flash basically as a video decoder, and provide a downloadable video file separately from the Flash player. Certain web browser extensions or third-party programs exist which can make the task of downloading this file to your hard drive as easy as a click of a button.
Some such programs provide a way to convert your downloaded videos into a media format playable by common media players on the desktop; other programs do not provide such a feature so you either have to have a media player that can play the files, or convert them manually using something like ffmpeg or avidemux.
There is no need for me, or anyone, to provide you with a list of software programs that will download videos intended for Flash streaming to your hard drive. Legality aside, you are more likely to find a program that fits your particular situation by googling for terms such as "download flash video" or "flash download helper". Be wary that you should carefully evaluate the reputation of any company selling or giving away software of this nature, as it is fairly likely to contain some form of malware due to the general popularity of this type of program with users who can best be described as "gullible".