 If you liked K-On!: Ura-On! |  ...then you might like Shingeki no Kyojin Picture Drama |
Both are short specials, made as spin-offs of original series. Both have chibi-styled characters and are based mainly on comedic dialogue. Both are comedies and both have short episodes. Difference is that Shingeki no Kyojin Picture Drama comes froum shounen anime while K-On: Ura-On comes from slice of life anime.