I know you can't copyright gameplay, so I can clone a succesful game. I'm not completely sure if you can completely take over all the rules (when rephrasing them to go around copyrights on text).
But my biggest problem is, how do I make my game findable for users? Should I use a name that looks like the original trademarked game, like e.g. iRisk (for iOS), or R7sk (for WP7) ? Should I go for another game that grasps what it's about (e.g. Conquer the world) and add 'RISK' (or a similar reference) to the game description?
Edit on Tetrad's comment: People are free to propose an alternative solution to name the game as implied in my question. I'd even like to alternative solutions of close to the border trademark names, to prevent any problems on that part.
Cloning games and certainly puzzles (like sudoku) has been used a lot and sometimes it's even good to bring it to a new platform (mobile, ...). I'm mainly looking for a way to make the game findable for users, because as for now it's not available yet on the 2-3 platforms I'm looking to develop it for. I want users on these platforms to be able to play the game, without having problems with the trademarked name.