I have Comcast cable internet and TV, with various drops around the house including one in my office.

Sometimes it would be nice to be able to watch TV in the corner of my monitor as I work. I do not have a TV tuner in my computer but it should be a trivial matter to install one.

Can I just split the cable at the wall jack then run one cable to my cable modem and the other to a TV tuner card? Or is it more complicated than that?