Freenom - Provides free website domains using .tk, .ml, .ga, .cf, and .gq.
No-IP - Dynamic DNS and Managed DNS Provider
FreeDNS by Afraid.org - Free DNS hosting, lets you fully manage your own domain. Dynamic DNS and Static DNS services available. You may also create hosts off other domains that we host upon the domain owners consent, we have several domains to choose from!
Duck DNS - Free dynamic DNS hosted on Amazon VPC
EuropNIC - Your own website with your own free domain, free e-mail addresses, free webspace, no costs!
NameCoin - Namecoin is a distributed domain name system based on the Bitcoin technology.