1x21 A Landmark Story
Title feels kinda self congratulatory, with nothing to justify it in the episode's actual story.
Lego Star Wars
The Padawan Menace
The Empire Strikes Out
These two made-for-TV CG specials are quite fun, actually, with nods for adult fans as well as silliness for kids... and also adults.
Not Going Out
[Watch it (again) in HD on iPlayer.]
3x06 (1/12/12 edition)
1x02 Episode 2
[Watch it (again) on ITV Player].