Well, There are many ways to invest it. Altough most of them is more like a long term investents. You can buy some small site, that has already some earnings by Adsense, take care of it and make it better earn more. You start up a proxy network. To see smoe free templates and a list of hostings see my footer links You can start up a site with affiliate program, Advertising it on Google Adwords or so. Find someone with idea and invest in it. Do share like 60%/40% and earn from someone work being his money support. Well, i think the easiest would be to start up a proxy network, because You have some cash on domains, servers and advertise. If You do it properly You can have 150%-200% of your investemns and the end of first month .
a proxy site could be a good idea but i think proxy sites are saturated now..there are thousands out there so it'll tke a while to actually get there..unless u have some crazy,innovative idea to grab ur visitors..another idea would be to purchase some hosting and start a blog..post around 15 posts and then advertise with the rest of the cash i doubt u'll get 150 to 200% in ur first month but its pretty much long term and with time if u maintain it,,u'll probably not regret the investment..
you could buy 10 domain names and get some cheap hosting and spend a week writing articles about the different domain names. Once you have written 5-10 for each, go to oswd.org and upload the articles on each domain. You could then sell these sites for $20-$30, hence making $100-$200 profit. There are unlimited ways to make money from that, just be creative and use your imagination. Good Luck!