I was trusted the strange mission on finding a game my wife used to play and by her description, it was an Interactive Fiction!
All she may recall was the character trying to escape a house and having to solve many puzzles connected to math and calculus. Also, she described an interesting resource where the game designer created fake Internet pages. Using in game links, the player could access this pages which were actually on line to gather more clues to solve puzzles.
Does anyone have any idea what game she is talking about?
I don't know, but it'd probably help narrow it down if you mentioned how old the game is (or how long ago she played it), and whether it was a parser game (where you enter commands) or a choice game (where you choose from pre-defined choices).
Here are some games with math related tags on IFDB:
The girls said the used to play online during 2010, but are not sure it it was parser or point and click. They guess it had only images as pictures, but not graphics.
I believe the real kick here is the fact of using links and Internet connection to send players to Web pages made only to deliver clues in the game.
Maybe someone else here will have some ideas. If not, you could also try asking at this forum: http://www.intfiction.org/forum/
I don't think these are what you want, but here they are, lol:
PC/APPLE (Mac computer back then): 7th Guest and its sequel 11th Hour (these do involve trying to escape from a house and have some pretty advanced and really cool/fun puzzles --- some of them probably could use calculus... I was young when I played these on my Mac many many many years ago, lol. So, calculus was very above my ability and knowledge level, lol)
NES: Maniac Mansion (this is defintely not it, as it doesn't use advacned math puzzles, but it's still an awesome game, to this day, hehe)
NES: Shadowgate (this too is definately not it, as it doesn't involve trying to get out of a house, lol, but it's still an awesome game)
We checked one by one. The girls said it was more about investigation and not horror.
I still thinking the major Trait was the use of online websites to supply the in game information and clues.