Based on a series of children's books, the Time Warp Trio joined the NBC/Discovery Kids block in July 2005. Co-produced by PBS affiliate WGBH, the series is a rare entity in that it has never aired on PBS. The producers instead sold the series first to Discovery Communications, and the Trio would ultimately wind up on NBC.
The basic plot is this. One of the trio receives a mystic book from his uncle, a magician. Said uncle departs before he can explain the contents of the book, and that leaves our heroes to fend for themselves. It's not quite like the live-action primetime shows like Time Tunnel or Voyagers!, or even Cartoon Network's Time Squad, which predated the Trio to the air by 4 years. The boys do make it home after each adventure.
Here's the intro:
Unfortunately, Time Warp Trio was cancelled after 14 months on NBC, and continued in reruns on Discovery Kids until it was converted to The Hub last year. The flash animation used on the show is an easy culprit, but it's not at fault. The books on which the series is based weren't that well known to most viewers, and the series was not heavily promoted at all. The Hub hasn't retained very many DK properties since the conversion 13 months ago, but one can hope that if they are shopping the Trio, PBS can finally take a look.