How Can I Make Some Money From Spare Domains?

I currently have just one website which is really just a personal site but I do sell a few things through it as well as Adsense and although Adsense only generates a few pence a month the odd sales I make do generate enough money to basically pay for my hosting for the year.

However this hosting is coming up for renewal in December and I've made the decision to change hosts not because I'm not happy with my current host but simply because with the new host I've found I get a lot more for a lot less. The new hosting package I have in mind allows me to to have 4 separate websites (or 6 if I pay the same as what I'm currently paying) with 5x as much disc space as I which is way more than I need to host just my current website.

I do own another 4 domain names which I've never used and with a new host I could now make use of them. One of them is photography related, 2 are genealogy related and 1 is lifestyle related. The trouble is that I don't have the time to build another site from scratch similar to my existing site but I would like to try and earn a bit of money from the sites. I am realistic though, I'm not expecting to make a fortune and fully expect it to be just a few quid here and there and that's the rub. Because I know that I don't have the time or skill to make a site that would generate any significant amount of money I can even less justify spending much time building new sites and writing lots of content for them.

Are there any avenues worth exploring or am I wasting my time?