Dear Rich: I have a question. I would like to create an online game that is similar to a popular board game. How I can do this without getting sued? I'm so glad you asked. Initially, I must remind you that there is no sue-free solution to anything. Anyone who can afford a few hours of a lawyer's time and some filing fees can sue you. However, what I think you're asking is: How do I lower the odds of being sued and reinforce the chances of victory in that lawsuit?
Start with the principle that the underlying ideas for games are usually not protected. For example, many companies have created online games based on hangman, but you'll run into a problem if your hangman game is expressed in the same way as Wheel of Fortune. To lower the odds of becoming a defendant in a lawsuit, do the following:
Don't use a name that's similar to a popular game. Stepping on the trademark of a game (particularly a famous one) is a surefire way to get dragged into court (although, occasionally the results are suprising).
Avoid copying the appearance of the packaging. Game companies feel the same way about their trade dress as they do about their trademarks (Just ask the makers of Sexual Pursuit).
Don't copy text or artwork from the game. In that case you'll be stepping on someone's copyright and unless your use is excusable under fair use or similar principles, judges may not be sympathetic. However, the copyright in some board games, such as Scrabble, may be 'thin' and harder to protect.
Check to see whether the game is patented. Yes, some games are protected under utility patent and design patent laws. Patent infringement lawsuits are a real drag, so check it out before your game goes live.
Move to a country where it's unlikely the game company will want to sue you. Unfortunately, in today's global village, that's becoming harder and harder to do.