In Your House was a pay-per-view (PPV) series made by the World Wrestling Federation (WWF).
The original idea was in months where the WWF was not producing a major PPV event (WrestleMania, King of the Ring, SummerSlam, Survivor Series, and Royal Rumble which ran for three hours) they would produce a two hour PPV event for a lower price of $19.95.
When World Championship Wrestling (WCW) started producing three hour PPV's on a monthly basis, the WWF was forced to drop the concept.
The events were numbered numerically (example: In Your House #1, #2) until In Your House #7 where specific subtitles were added which usually referred to the main event, starting with In Your House #7: Good Friends, Better Enemies (refers to the Shawn Michaels vs. Diesel match).
Gradually the subtitles became "In Your House" (example: Unforgiven: In Your House). Current PPV's No Way Out, Backlash, Judgment Day and Unforgiven all came from the In Your House series.