As per Meg and (I think) Joe's request, I'm posting this here.
Roaming across the internets, I stumbled upon osu!, a rhythm game that's essentially a PC version of the DS game Elite Beat Agents. What's much better than Elite Beat Agents, though, is that this is made by nerds for nerds, so almost all of the songs/beatmaps you can download from the site for the game are videogame/anime related. It's also amazingly fun and amazingly addicting.
In any case, this has already provided me with hours of procrastination, so I thought I'd spread the love.