$500 from Poker Stars

[Vyse]

Checking my bank account today at Wamu, I see this:

Date Sort Descending Description Check # Debit(-) Credit(+) Running
Balance
12/27/2006 Pstarpayments 8888664442 99991A009366471 +$200.00 ------
12/27/2006 Pstarpayments 8888664442 99991A009366467 +$300.00 ------

In other words, Poker Stars inserted $500 total into my bank account. How / why? As of now, I'm assuming this is NOT really my money, and am not going to spend a dime of it without waiting a month to see if it actually stays there. Suffice to say, though, that I am extremely confused. Anyone else experience this? I'm thinking maybe it's related to the whole anniversary / Christmas bonus thing, but why wouldn't they send an e-mail to tell me?