You can't. You would need express permission from every owner/copyright holder of the show or movie you show.
In other words, you can, you need express permission from the copyright holder or for the copyright holder to have already surendered their rights to the material.
In the real world, a DP poster can't do it. Hulu is paying about $50 million just to show The Daily Show & The Colbert Report.
what i would do is set up a site and host the videos of loombo (cause megavideo sucks) and embed the video in your site and clearly state on your site that no copyright is breached because video content is hosted on another site (loombo video hosting) a good example of this method is the iwatchnetwork they own over 50 sites such as 'iwatch24' 'iwatchsimpsons' etc that work on the idea i describe above hope this helps
Unfortunately embedding makes it no more legal, ask Napster or The Pirate Bay, both who argued that they didnt host files