The Old Dark House (1963)

This horror/comedy from the masters William Castle and Hammer Films is a remake (more in name than plot) but is actually quite watchable as long as you realize that it is just silly, wacky fun.

Our hero Tom Poston has befriended the odd Casper Femm (Peter Bull). They are actually roommates; one uses the apartment during the day, the other at night. Femm asks Tom to join him at his family estate somewhere in the North. When Tom arrives he meets the insane Femm Family who mysteriously start dying through-out the night.

Available: Amazon, Netflix