It's legal so long as you change the name, and don't use the same graphics. I made a website for a fork of UNO years ago called "Hot Death UNO" and was sent a

It's legal so long as you change the name, and don't use the same graphics. I made a website for a fork of UNO years ago called "Hot Death UNO" and was sent a cease and desist from Mattel for it. I changed the name and the look of the cards and poof, no more problem.