Anime Fest has had what's labeled as Anime Idol hosted by Mu Epsilon Kappa (MEK) the past few years. ChibiBritt will post once they've been confirmed for programming with additional details. I know there's been generic karaoke in the panel rooms in the past, but I'm not sure if it will be around this year.
I don't follow the gaming things, so I do not know if there is DDR.
As for cosplay, Anime Fest has split the two competitions apart. There is the walk-on (not exactly a hall costume) usually on Friday night, where you walk across the stage and pose in your costume. The skits portion is usually Sunday night, and consists entirely of skits.
As for other things, Afest has a 24-hr video rooms starting around noon on Friday going through about 3pm Monday afternoon. The past two years there have been 4 video rooms, all running the full 24 hours.
Every time I open the fridge, the hole in my jello glares at me.
Thank you for completely removing my signature without emailing me that it was too long.