can you lease out a website? I am thinking of doing it for my forum can it or has it been done before?

What do you mean by "lease out"? I know what the term means, but I have no idea what you are saying you want to do with your website.

Rent it out to someone they could place their ads on the site and run it while paying to run an already active site.

Huge amount of legal issues here. Who is going to own the content that's on the site currently? Who's going to own the content that's generated during the lease period?

Also, why exactly do you want to do this? It seems like it would be an overly complicated situation, that many people wouldn't be interested in.

Well its a forum so most of the content is user generated.I have planned to sell the site because I do not have the time to look after it I also dont realy want to sell it but need the extra cash so leasing it out sounds like a good option for me.

I doubt many people would want to point time and money into promoting and maintaining a site when they can't keep it for the long term. It's not really a good investment on their part.

If you need the money, you're probably going to just have to sell it the traditional way.