Ask HN: Category structure for a directory of side projects

I am thinking of creating a web directory of side projects (as a weekend side project of my own).

TL;DR: Inviting category structure suggestions for a web directory of side projects

All will be able to submit their side projects to this directory (and the listings will go live immediately upon submission).

I'm sure it would make (a lot of) sense to have a category structure on the directory so that projects can be listed/browsed under relevant categories.

I'm currently setting up the basic directory (site, using the WordPress CMS and some suitable plug-ins) but I am not able to think up a category structure. While I am configuring the project submission form so that users can suggest categories, I would prefer to seed the directory with (at least) a decent category structure ab initio.

I invite and welcome any/all category structure suggestions from all here. (All other suggestions welcomed too.) TIA :-)

(Those willing to take a sneak peek, here is the [barely] working URL - nothing listed yet, but you should be able to submit/list projects: http://sideprojects.tk/)

Edit: When fully done, I'll do a Show HN thread here.