Daedalus was a serious design by the British Interplanetary Society, for an interstellar flyby mission that would reach Barnard’s Star in 50 years.
There’s some more info in this video I made:
Here’s a BIS page on the project:
http://www.bis-space.com/what-we-do/projects/project-daedalus
And another nice article by David Darling.