Anyone here with a DS and a game cart is free to have a battle/race game with me. I've got a lot of DS games Friend Codes listed:
fc.nishmudkip.com or fc.nishant.me
Choose to add me on either one of them, or if you have something else to play, let me know and I'll get that.
You can directly contact me for a Wi-Fi meet through the form on that webpage.
