You might want to check out PlayOn
. You have to run it from a PC with at least a 2Ghz processor, but you can get a lot of channels you wouldn't otherwise. It's worked with games on ESPN3 for me, but I haven't tried ESPN.
I can run PlayOn on my laptop and stream the feed to my Roku box, which is nice since I don't have to mess around with hooking the laptop up to my TV.