This has been circling the Internet for the last number of days and I thought since there is so much rubbish on TV right now that it woould be a good enough time to post it. It's YouTube video of the old David Letterman Show that aired in 1980 in the morning on NBC. I actually remember seeing this show on TV, but then again, back in 1980 I watched everything on TV anyway.
On the negative side, Dave's morning effort was a notorious bomb: it only ran for 19 weeks. On the positive side, though, it was a good show that got a cult following of loyal viewers, and it did win two Emmys. The show may have been a flop, but obviously Letterman made a good enough impression to be invited back to do a new and better show in late night -- where he belonged.
Here's a look at the first several minutes of a typical episode of The David Letterman Show from 1980 and you can check out the links to the rest of the show.