Puzzle games

Puzzle games are always fun...... well i guess they are fun or not. Some people get them, some people dont. I happen to be one of the few who enjoy a good puzzle game. For those of you who remember the game MYST.... you feel my puzzle pain. that was a puzzle game that got me into loving puzzles. Puzzles make the player really think about it in ways they probably wouldn't have. Try to remember your most puzzling puzzle and what game was it on? Tell me about the hours put into it and whether you gave up or.... sorta cheated. I am looking for ways to incorporate a good puzzle in my game.