ideas on Monetising email list

HI all I could do with some help here as I have a 40000 email list carefully collected from construction and architecture industries in the uk
i know these industries arn't doing too well because of the recession but I would like to know in this can be monitised?
any ideas guys?
Thank you

ask yourself, what an arhitect would love to download?
answer: secret blueprint of new skyscraper in London? :screwy: or maybe free xxx paswords?
choose one or mix both

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sell them on the idea you know how to generate business for them on the internet, but you need to have a plausible plan, can be buying advertising or something of the sort. Start by giving them 5 websites they can advertise on to increase their business. Give all 40K the same 5 websites, but keep a good one or two websites to yourself for future use.

Yes. Just solve a problem they have in common