Part II: Alyson Hannigan reveals her favorite and least favorite 'Housewives' and Zachary Quinto picks the creepiest scene from 'American Horror Story.'
Part I: Zachary Quinto tells all on 'Plead the Fifth' and Alyson Hannigan dishes on who she keeps in touch with from 'Buffy.'
Alyson Hannigan & Zachary Quinto answer Andy’'s nerdiest questions on 'Star Trek Into Darkness' and 'Buffy the Vampire Slayer.'
Alyson Hannigan spills the beans on all things 'Buffy the Vampire Slayer' on 'Plead the Fifth.'
Zachary Quinto and Alyson Hannigan guess whether the fan portraits are 'Sci Fi or Oh My!'
Alyson Hannigan teaches Andy Cohen how to sign an autograph with his foot.
Andy reveals if another 'Housewives' franchise is in the works and shows off his birthday present from Jimmy Fallon!