Peter Capaldi with some very young fans, at the Doctor Who Experience, celebrating 10 years of NuWho:
I love how Capaldi stays in character, and keeps the kids engaged, all while retaining the spiky presence that makes him more of a challenging Doctor in the Hartnell-Baker-McCoy mode. His quick thinking on the potentially dangerous question "who was your favorite companion?" is admirable, as is the emotion he brings to his answer: His lost grand-daughter.
You have to love how he can relate to the kids without condescension.
The bits with Steven Moffat are pretty fun, too.