The CW Seed website currently offers hundreds of hours of shows like The Flash, Terminator: The Sara Connor Chronicles, and every Whose Line is it Anyways ever made. Now it is all available on your Roku! In total there are 39 shows available on the CW Seed service through your Roku!
You can add the CW Seed channel to your Roku here: https://channelstore.roku.com/details/71698/cw-seed
From the Roku description:
Developer:The CW Network
Watch hundreds of hours of your favorite shows, every Whose Line ever, and CW Seed original comedies, all for FREE.
From the CWSeed.com website:
Q: What is CW Seed?
A: CW Seed is The CW’s digital home for comedy. We’ve got original shows like the Veronica Mars spin-off, Play It Again, Dick, and a little something we call Every Whose Line Episode Ever.
Q: But EVERY one? Weren’t there some with British —
A: We dare you to find an episode of Whose Line made in America that isn’t on our site. Also, George Washington, King George, 1776, etc.
Q: So you’re not The CW?
A: No, we’re the younger sibling that didn’t get as much parental supervision.
You can read more about the CW Seed service here: http://www.cwseed.com/cwseed-about/