Paradox Interactive is starting the week's PC game sales on the early side today. The PC game publisher is celebrating its 10th anniversay this week by putting all of its games on sale for 50 percent off at the various download sites that sell Paradox's titles.

That includes outlets like Steam, Direct2Drive, Impulse and GamerGate, the latter of which Paradox started in 2006 but then spun out into its own company. The 50 percent off sale does not include pre-orders for upcoming Paradox Interactive games like Hearts of Iron III and East India Company.The 50 percent off sale ends on Sunday, July 26.

In related news, GamersGate has also put a collection of three games in the Crazy Machines puzzle series on sale for a total of $39.99 this week. And for today only it has also put Red Faction II on sale for 50 percent off its normal price.