i downloaded the "network stress testing" tool the groups are using to carry out the DDOS attacks. The code is less than 1 page..
I typed in the ip of my LAN router and started flooding it, it was brought down immediately. I tried it on another connected PC to the LAN, brought that down too.

Instead of an IP you have the option of typing in a URL or connecting to the "hive". Its quite effective. A small group (10 or more) using this tool would be able to effectively "stress test" a small scale site and see results.