eBay has an affiliate program. Thus, if you send users to their website and the user places a bid on an item, you earn a commission of that item’s sale price [or you earn a per-click fee]. So, the idea for this website is that you basically scour eBay and find weird and cool stuff that is for sale on eBay; stuff people don’t ordinarily see for sale. The items all display on your website [you can use eBay’s API, or you could simply copy/paste item title w/thumbnail and use your affiliate link to link to the item for sale].
I’d definitely have a daily email newsletter, so you’ll want to capture visitor’s email addresses (“Sign up for our daily newsletter of weird and cool stuff for sale on eBay, now!”).
(this idea is from November 14, 2007, but is being shared with you today)
I’m going through the past few years of ideas that are in my moleskine notebooks. Some of the ideas are really lacking, but might give you an idea? All of these ideas are yours for the taking. Don’t forget my archive of 100+ web startup ideas.