It might be possible to clone your gists into a local folder (as pointed out by vgoff), then build some sort of personal website around this hosted on github pages... Using Jekyll/liquid you could tag and have categories... Embed using JavaScript, or use partials to inject code into the source ( using pygments to handle the syntax highlighting - or do it client side e.g using SyntaxHighlighter ). Perhaps use google search for the search component... or dynamically build up a json file, or use github's gist API ( http://develop.github.com/p/gist.html ) to pull in json for meta data and public repos...
You could possibly take this further and "demo" your HTML/CSS/JS gists using jsFiddle.net (you can create a new fiddle from a gist... See: http://doc.jsfiddle.net/use/gist_read.html )
I'm going to need a system like this for a project I'm working on ( http://getfiremonkey.com ) - it's for teaching teenagers HTML/CSS/JS in Firefox... And I'm thinking of building it on top of Github Pages/Gist/jsFiddle.net ... Free, open, interactive examples and branchable.
I've decided to setup a side project to focus on building a Gist CMS from anything I learn along the way...
https://github.com/chrisjacob/gist-cms
"Personal Gist CMS hosted on Github Pages. A code / content management system powered by Jekyll to tag, categorize and search your Gist archive. Keep all your Gist's organized in one repository; and show them off the the world with their own dedicated website."
Right now it's just an idea; so let me know if you're interested - and lend a hand if you can ^_^