My latest thought, mainly motivated by the lack of space in the house, was to look into an outdoor bog garden. I reckon I'll have to wait until the spring for this, it's probably not the time of year now, but I can start dreaming. Also, being the impetuous type, once I've come up with an idea, I have to check it out right away. So, I went to the Bog Gardens section of the site with the intention of asking a question, and found that several people had got there before me. Great, means there are answers already!
In particular, I found this excellent thread started by Floydsdad. This had several advantages for me over the other posts there. First, it was started last January, way before I got into this hobby, and has been updated ever since, so there's a good follow-up. Secondly, he's added loads of photos, so we can see what he did. Thirdly, and maybe most important for me (psychologically at least), he only lives a few miles away, so I can have confidence that if his bog garden can survive here in tropical sunny (ahem) Manchester.
So, off to the phrontistery (fancy word for a place where you go to think) to plan this out. Hopefully I'll keep a record of what I did here.