For some reason the creators at Dr. Who decided to make a couple of animated episodes* starring David Tennant as the 10th Doctor. Hold on . . . .
. . . . the Interweb has informed me that both of them were created as serials** and released on several different websites and the like over the course of several weeks.
Doctor Who: The Infinite Quest
This one has Martha Jones travelling with the Doctor on a quest to find a space ship (The Infinite) that can apparently make your "greatest desire" come true. There's actually very little to do with the ship and mostly it is a series of vignettes in which the pair track down the four pieces that will lead them to the ship. Now that I know it was released as a serial it makes much more sense as each piece is pretty much a stand alone mini-adventure. Nevertheless they do a good job of giving it that "Doctor Who" feel. The animation isn't bad, though a lot of the time the Doctor doesn't really look like David Tennant at all. Also the main bad guy is kind of a tool bag. In the sense that I kept thinking to myself, why doesn't the Doctor just trick him into falling into a hole or something.
Doctor Who: Dreamland
This one has the Doctor travelling alone. He ends up in the desert in Roswell, NM looking for some chili from a roadside diner. He ends up running around with the waitress and an American Indian*** guy. They save the Earth from being taken over by aliens. Of the two this one has much crisper writing and the plot flows better. But of the two this one is much less a series of small episodes. The animation in this one is unfortunately a little worse. Mainly in the people. They are clearly computer animated and they move with that stiffness that cheap animation gives people. Though on the plus side the Doctor looks much more like David Tennant.
Both episodes are relatively short (~45 minutes) but if you like Doctor Who at all they are worth watching.
The Infinite Quest: B+
* - There are apparently three other animated episodes, but they came well before these two and star other Doctors.
** - Meaning, released in small snippets over time and having nothing to do with breakfast
*** - Though at times it's hard to tell that's what he's supposed to be.