What does this mean ?
I'm on the couch tonight for sure
From the movie Judgment Night (1993).
The usual interpretation, I think, would be "I'm going to be sleeping on the couch tonight". This means that the person's partner will not allow them to sleep in their shared bed, because they have done something wrong or because they are somehow unacceptable as a bed partner (they are drunk, they smell bad, or anything like that!)
Without more context, I can't be entirely sure that this is what is meant, but I think it would be the most common use of this phrase.