Steam has knocked 75% off 13 popular indie titles when purchased as a bundle called "The Potato Sack." Interestingly, the pack launched on April Fool's day and contains clues for an ARG (Alternate Reality Game) that many believe is related to Portal 2, which is slated for launch on April 19. Before you dive into the deals, we should note that BioWare is giving Dragon Age II owners a free copy of Mass Effect 2. In other words, if you intend to buy or already own the former, don't purchase the latter.

Steam
The Potato Sack $38.72 (75% off -- contains 13 indie titles including some of the following)
Blood Bowl Legendary Edition $9.99 (75% off)
Super Meat Boy $7.49 (50% off)
Amnesia: The Dark Descent $9.99 (50% off)
AudioSurf $4.99 (50% off)
The Killing Floor Bundle $13.97 (50% off)
Bit.Trip Beat $4.99 (50% of)
Defense Grid: The Awakening $4.49 (50% off)
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Impulse
Focus Home Interactive RPG Bundle $15.98 (60% off)
Elemental: War of Magic $19.99 (50% off)
Mass Effect 2 Digital Deluxe Edition $19.99 (50% off)
Aveyond Bundle $18.49 (50% off)
Asgaard $14.49 (50% off)
Metal Brigade Tactics $2.99 (70% off)
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GamersGate
Hearts of Iron III $5.99 (70% off)
Xenus 2 White Gold $14.98 (50% off)
Precursors $14.98 (50% off)
Ship Simulator Extremes $13.98 (65% off)
Warfare $7.48 (50% off)
Recettear: An Item Shop's Tale $9.98 (50% off)
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Direct2Drive
Grand Theft Auto IV: Complete Edition $9.95 (75% off)
Up to 80% off "transportation" games
20% off all games via coupon code "SHOWERS"

EAStore
Mass Effect $11.97 (40% off)
Mass Effect 2 $11.97 (40% off)
Dead Space $11.97 (40% off)
Crysis $17.97 (40% off)
Crysis Warhead $11.97 (40% off)
Battlefield: Bad Company 2 $11.97 (40% off)
The Saboteur $11.97 (40% off)
Mercenaries 2: World in Flames $5.97 (40% off)
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Good Old Games
1C Collection $37.92 (50% off -- 8 games)