Games causing severe permanent lag spikes - Internet works fire

I'm baffled. I really don't know what could be causing this.

I'm using a Linksys WMP300N Wireless-N router with a Ralink (Sabrent) Wireless-N networking card.

Every 2 or 3 days, this happens : I'll turn my machine on - check my email, make my rounds of various websites, then try to play a game. It will be fine for a couple seconds, then my ping will shoot up to anywhere from 1,000-15,000ms - and it doesn't stop. I've let it sit there for 10 minutes, came back and it was still at a completely unplayable, miserably pathetic ping. Every game that I try to play online is thereby impossible to play until further notice. In addition to the miserable pings, I get a stuttering, buzzing sound that will come on and off at 2-5 second intervals. Quite irritating. There is ZERO playability. Sometimes it wil read that I have zero upload speed, and sometimes it will read that I have zero download speed. So, at that point i'm doomed to sitting around and waiting for what typically is about 8-14 hours before the issue magically fixes itself. The games just...work...again. I've changed absolutely nothing. So, it'll work for another 2-3 days and then it'll just happen again.

I will log off of whatever game I'm trying to play, and go hop on the internet - everything works perfectly fine. Speed tests show that everything is working above and beyond the call of duty. What is it about games that are effing up my networking? I've never had ANY issues surfing the web.

I'm using a corporate release version of Windows 7 so the WZC-turnoff method isn't an option. I can't imagine that it's anything other than my wireless card or router, but I'll give you a quick rundown of my system core components for good measure.

EVGA X58 Tri-SLI
Intel i7 -920
8GB Corsair Dominator 12800
ATI HD 4890 XXX (x2 in crossfire)
1TB Hitachi HD
800W PSU