Electronic Arts knocked $10 off the PC download of Battlefield: Bad Company 2 - and someone else found a promo code that takes an additional $20 off - for any game - making it $19.95 until the end of the day.
The offer is good over the EA Store; enter PAXEAST842 in the promo code field to take the extra $20 off. The code also seems to be good for any other game purchase in the store, PC or retail. I applied it to Mass Effect 2 and EA Sports Active and it was still valid.
EA says the $10 off BFBC2 ends today. The site says nothing about the PAX promo's expiration but one can assume that it lasts only as long as the Expo, which ends today.
Thanks to breadtruck for spotting this.
Update: Reader Chris says a card accompany the promo code at PAX East says it's valid for new orders only, with a minimum purchase of $39.95 required. The promo code expires April 9.