There are two shows each week on television that show how the experts find ancestors for celebrities: one on Fridays at 8 PM on NBC, the other on Sundays at eight PM on PBS.
The first is in its third season, "Who Do You Think You Are", sponsored by Ancestry.com. It is on NBC Friday nights at eight PM. If you want to catch the previous shows, they are available in streaming Internet video at this website.
The second show is "Finding Your Roots" and is a repeat of the original season shown four years ago. The first show this year was last Sunday, a two-hour introduction. It is available at PBS here. It is showing on PBS every Sunday night at eight PM through May 18th.
I find both of these shows to be interesting and informative. Sometimes I find out about a technique for finding ancestors that is new to me.
If you feel you need some inspiration to get started on researching your family tree, I recommend both of these shows, which are also very entertaining.