I wanted to build a site like this a while back, but, similar to many of the ideas on "The Half Bakery," my idea remained unfulfilled. The idea for the site is simple: people post half-baked ideas and the rest of the community members vote on it. Non-members can browse around as much as they want, members can post, comment, etc.
Some of the ideas are truly stupid, but if you search by "best" you'll see some really good ideas. The site is entirely text-based and very easy on the eyes. The navigation is a bit odd, but not confusing. My only complaint is the registration process, which requires you to send an email to request membership. I'll write more when I hear back from them.