The House of O's

SynTax
You begin the game outside the typical (American) suburban house of the O's, and after finding a way inside, you can ask Mrs.O various questions which might help you in your task of tracking down the elusive Mr.O. [...] Finding Mr.O isn't too hard, if you've taken your sleuthing seriously and read all the bits of paper, messages, etc. left lying around the house. Persuading him to follow you, so you can return him to his spouse and claim your reward, is a different kettle of fish. This bit requires much to-ing and fro-ing, and lots of patience.
See the full review