Jesse Eisenberg's amiable skittishness has become his calling card. He's the nervous, jittery, quick-talking Everyman reluctantly drafted into the war on the undead in "Zombieland" who could also channel his dorky appeal to portray Mark Zuckerberg in "The Social Network,

Benji has been emotionally adrift since she died — they were very close — so this trip is his way of honoring her. So begins “A Real Pain,” the funny, bittersweet road trip dramedy written and directed by Eisenberg and based on his own family history.

Writer-director Jesse Eisenberg's “A Real Pain” strikes an almost impossible balance. It’s part comedy, part tragedy. It’s part road-trip saga, part odd couple-buddy flick, and part Holocaust film. Somehow,