Replying to Laptop as tv/monitor?

Is there any possible way that anyone knows to be able to hook up a video game system to a laptop so you can use the screen as a TV type of thing?   Maybe a monitor plug-in or an S-video cable type of thing?  I'm not talking an emulator or a capture card because its a laptop.  I know there are external capture cards and everything but I'm looking for a cord or converter plug or some sort.  I dont know if its possible but it would be cool. 

Thanks