I found out this weekend that if you connect your cable modem to a new ethernet mac address that Time Warner will change the ip address of the device pluggged into of your cable modem.... weird considering the 'cable modem' hasn't changed at all, it's just what... it was plugged into changed.
Now the cool part is i also found out that if you 'fake' the mac address using some cool software that you can swap around your address ad-hoc and when you 'turn off' the software if will go back to your original address... :)
Check out http://www.technitium.com/
Basically Technitium fakes the mac address change, you then simply power the cable modem back on, 30 seconds later you'll have a brand new ip address. As far as any sites are concerned you are a brand new visitor.
Turn off the software (eg mac address goes back to what it was before), power modem on....same old address.
Of course Time Warner will still have a record of who you are so dont go using this for anything illegal - but it certainly opens up some nefarious possibilities.
Also I'm not sure how long you can leave your fake software mac address on before the Time Warner dhcp server 'allocated' your old address to someone else though.
Also if you use this in conjunction with No-Ip domain registration/DNS software you can even setup websites on 'fake' ip addresses temporarily.
lol - like i said time warner will still have a record of who you are so dont do anythingyou shouldn't be.