good medicine: kid casting
I'm a complete movie and TV geek so I immediately fell for this tumblr. I particularly enjoy when shows/films feature a younger version of a character. It usually prompts "what, oh my god they look nothing alike" (which I secretly get WAY too worked up over and involves mental hair pulling) or "hell yeah, perfect casting" (which involves unnecessary and lame mental high-fives with myself). So if you're a dork like me you'll enjoy this site called Kid Casting.