Carnival Phantasm Episode 4: Badump Date Super Plan
Episode 4 of 12 of Carnival Phantasm, aired August 12, 2011, 15 minutes. Available with English subtitles and dub where released.
Episode summary
The main protagonists of Fate/Stay Night and Tsukihime meet and discuss their problems namely how they can accomplish dating all the heroines of their respective games on the same day.