I do computer tutoring evenings and weekends. I just run a little 3 line classified ad in our local paper ($21 a month, so even one call a month more than pays for it). I actually run it completely legitimately as a side business (report it on my income taxes, etc.), however I know plenty of people that would do that sort of thing as cash under the table.  

You could do local typing (one idea is afterhours typing for business professionals traveling to local hotels, if you worked out a referral service for the hotel). The term papers mentioned above would be another option.

I would also look at home office professional organizing, where you meet with people in their home offices, help them get caught up on filing, better organized, etc.

Virtual assistants are not always daytime based, especially if you take clients that are outside your geographic area (i.e. the US being 6-8 hours behind the UK).

Writing might be an additional option. There are websites out there that pay for reviews, editorial content, etc. Some of them are quite low. Others give you pay for page views, which if you build up a loyal following can add up.

Marie