Gelato CMS is a open source Tumblr clone which has the same features as Tumblr. You can easily download and install Gelato CMS on your own web servers and start tumbling. Gelato also supports themes and plugins.
Say hi to our first ever Tumblr-esc WordPress theme. Make your WordPress installation look and feel like a Tumblr blog. 9 different post formats including 15 different color presets that help customize the look of each post. Along with 3 different column layouts for your pages this is definitely one of our best themes yet!