Here are a collection of Godaddy and Dreamhost codes that can be currently used.  These are all Case sensitive.

Godaddy

ZINE1 for 10% off
ZINE2 for $5 off any $30+ purchase
ZINE25 for $25 off any purchase of $100
ZINE3 for $7.49 .com domains
MTECH1 to get 10% off anything
MTECH2 to get 20% discount when you spend 50 dollars or more
MTECH330 to get 30% off .com domains
EMMA1 DARK1 PETE1 WALK1 OYH1 HASH1 CHILL1 ZINE1 ROCK1 CHH1 RRTV1 MTECH1 10% OFF Entire Order
gdd1101c 10% OFF $40 OR MORE cjc695b2 $6.95 .Com (New Registeration,Renewal or Transfer)
gdp0627 30% off .Com .Net .Org .Biz .Us .Name New Registeration, Renewal or Transfer
gdp0518a Get a NEW .INFO, .NET and .ORG for $15.00
gdp0616a Save 15% saving on all web hosting plans
cjccabone / cjcheaone Save 1$
cjccab10 Save 10%
cjccab30 / cjchea30 Save 5$ off 30$ or more
cjccab50 / cjchea50 Save 10$ saving 50$ or more
gdp0615a Save 15% when spending 50$ or more.
cjcdeal Save 15% off 75$ or more
gdp0629b Save 20% 50$ or more
cjc20off75 Save 20$ off 75$ or more
gdp0609a Save 20% off 75$ or more
gds0124a Save 25% when you spend 75$ or more
gdp0616p Save an extra 15% on WebSite Tonight 12/24/36 Month plans!
gdp0601b .Asia 17.99$ per year.
gdp0611w 30% off .Co.Uk Domains
gdp0608c .mobi Renewal  12.99$
gdp0607c Renew .INFO for 6.99$ first year and 8.99$ other years
gdp0537m / gdp0616m 20$ off Basic super or pro reseller plans
cjchstsale Save 20% for Shared Hosting Plans
gdp0537c / gdp0616k 15% off Dedicated Hosting purchase
promo10 10% off entire order
promo530 $5 off $30 or more
promo749 $3 off .com registrations, transfers or renewal

Dreamhost

OZSOURCE US$97 off yearly Dreamhost Hosting or $51 for monthly hosting.

Sources: digitalpoint, webmasterzone, godaddy