Well, they are more code snippets than plugins, but it was easy to integrate it inside my static web blog, using just JSONP calls. I think the Twitter API I'm using could be deprecated soon, but it worked for me by now, so it stays as is for a few time. I will separate the two elements (twitter/github plugins) from the default view just to make easier the copy and tweak of this code in your jekyll projects.
For twitter syntax highlighter I've reused a function I did for Sabrosous and it worked pretty well. :-)
I've also modified some things from the tag_list page, I think there were too much tags so I've limited the list to tags that has more than a post linked.
I'm really happy for the change from Wordpress to Jekyll, I love Git and now I manage every part of the content from a Git repository, really cool and easy. :-)