Wow, awesome so far!
Just a few ideas:
Add a column for "Description" or "Why this code is important/interesting)
Functional Area(s): <math>, <statistics>, <sorting>, etc (rather than just language), ie: method to do: <xxx> Category:<Statistics> , etc. (could get complictaed, but there may be a way to sort it out)
Related to that, an interesting idea (I've seen this elsewhere) is have well-known algorithm <x>, and then have people submit implementations in different languages (and I supose people could upvote the best implementation per language). For example, there are many different common algorithms known to the world of CS that have been around for years, it would be nice to have a hub where one could go to find these, and be able to see implementations of said algorithm in your language of choice.
You might want to implement a bookmark system and advanced search so people could tag things they want to read later, and advanced search would allow to search title, within description, only tagged, etc etc
A lot of what you should be doing for a site like this is the same thing stackoverflow has done, yet, it is distinctly different, and useful.
This could turn out to be a really great website! Stackoverflow has kind of explicitly avoided getting really deep down into the source code level, but I think there would be a really huge demand for such a thing if it was done properly, and nice work for 1 day!!
I hope you run with it, I think it's a really great idea that will work, if you put enough work into it!!