Ask YC: DDOS Protection?

Some friends of mine have been running into an issue with massive DDOS attacks, primarily massive junk UDP traffic. Right now, they're shunning IP ranges as fast as we can, but things change quickly, and often at night. I saw the discussion at http://news.ycombinator.com/item?id=106020 , which took place just under a year ago, but I'd love any advice. I know that there are companies such as prolexic and Gigenet can offer substantial improvements, if I understand correctly, by re-routing our traffic through them, and then on to us. Are there any companies that HN readers have worked with? What sort of pricing were you hit with? One quote I found online had suggested $400/Mbps/month. Are there any programmatic solutions to maintaining a shun list? I could script something to blindly telnet in, but it seems like there's got to be boxed solutions for this. The problem with most inspection techniques is by the time we accept the packet and start examining it, it's too late, and we start to get overloaded. Any advice would be appreciated.