Hannah was quite mistaken to think that Neville had better things to do on a Saturday night. Neville was not very good at socializing and when he went out he either ended up at the bar talking to Hannah or off in a corner alone, watching people. He wasn't a very socially competent fellow and even when girls approached him (which had actually happened since he had gotten into shape!) his awkward nature made them look elsewhere for someone to take them home. Neville had spent Saturday night at home ready about Herbology. That made him eager to get out of his flat and interact with someone. Even Gran had been some company when he had lived in her home.
When the owl came he rushed a response before running around his bedroom looking for some clean trousers.
Hannah,
That sounds fun. When and where should I meet you?