Nope, they do not if you are considering WHEN in time you watch TV. -Watching TV is enjoyable. --->This is more of a present tense, so you could be saying "watching TV is enjoyable" while you're currently watching TV (or have already watched TV in the past, so you're remembering the memory as if you're watching TV again in the present). -To watch TV is enjoyable. --->This is something more of a future tense, something that you probably haven't done.So you could be telling someone "to watch TV is enjoyable" without ever experiencing watching TV yourself, (which is weird, since most people have watched TV, so the sentence "to watch TV is enjoyable" sounds weird and unnatural)(Unless of course you are saying "are you going to watch TV?" or "They are going to watch TV" which are both future tense sentences, haven't happened yet. ---------------Better sentence for TO BE: "To be a doctor?" (something you haven't decided on yet for the future). To be an astronaut would be better (assuming you haven't experienced being an astronaut and you're imagining that it would be better if you did become one it in the future). ---------------Another example: "To be or not to be" Hamlet's question on whether it's better to be dead and commit suicide, or to be alive.