Actually, the fact that Mal was bored was a bit sad. I understand that playing games like Tetris wouldn't make sense for him, but maybe he could have some favorite shows and think of new versions? For instance, merging 'Friends' with 'Star Wars' could be quite entertaining.
I used that running gag as a way to signal that despite his ability to act (more or less) like a human, Mal's mind is very different from ours. He actually finds Guess The Output very entertaining, and is confused as to why the people around him don't understand why.
I agree; it's a very nice idea. After all, generating new media and many other forms of entertainment would heavily employ a random number generator, so why not go right to the core?