Assuming you won't be tied up with Borderlands 2, Torchlight II, XCOM: Enemeny Unknown or Dishonored, there are plenty of temptingly-priced timewasters to be found this weekend, including up to 75% off Focus Home Interactive titles at Steam, Batman Arkham and F.E.A.R. bundles for only $9.99 on Amazon, assorted Ubisoft packs at GameStop, steeply discounted EA titles including Mass Effect 3 for $11.98 at GamersGate, 75% off various Grand Theft Auto titles through several dealers, and more.

Steam
79 Wargame: European Escalation $9.99 (75% off)
55 Game of Thrones Bundle $17.49 (75% off)
65 Cities XL 2012 $9.99 (75% off)
74  Cities XL 2011 $6.24 (75% off)
69  Cities XL Limited Edition $3.74 (75% off)
73 Sanctum: Collection $4.74 (75% off)
80 Divinity II: The Dragon Knight Saga $9.99 (75% off)
74 Pendulo Adventure Pack $14.99 (75% off)
78 The Sherlock Holmes Collection $8.74 (75% off)
45 Confrontation $9.99 (75% off)
72 Dracula Origin $2.49 (75% off)
78 Double Fine Bundle $14.99 (50% off)
59  Apox $3.74 (75% off -- today only)
Loki $2.49 (75% off)
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Amazon Digital 
89 Batman Arkham Pack $9.99 (80% off)
72 F.E.A.R. Ultimate Pack $9.99 (78% off)
78 Darksiders II $24.99 (50% off)
75 Supreme Commander 2 $4.99 (67% off)
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GameStop
80  Sleeping Dogs $29.99 (40% off)
79  R.U.S.E. Bundle $12.49 (50% off)
81  Splinter Cell Bundle $11.49 (75% off)
71  Rainbow Six Bundle $7.49 (50% off)
80  The Settlers Bundle $19.99 (50% off)
93  TES V: Skyrim $35.99 (40% off -- also, Dawnguard for $13.99)
TES IV: Oblivion GotY Deluxe $12.49 (50% off)
TES III: Morrowind GotY $7.99 (60% off)
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GamersGate
63 Darkspore $4.99 (75% off)
81 Bulletstorm $4.99 (75% off)
67 Need for Speed: The Run $4.99 (75% off)
86 Mass Effect 3 $11.98 (60% off)
93  Mass Effect 2 $4.99 (75% off)
90  Mass Effect $4.99 (75% off)
73 Syndicate $10.48 (65% off)
88 Sins of a Solar Empire: Trinity $7.98 (60% off)
71 Alice: Madness Returns $4.99 (75% off)
74 Shank 2 $4.98 (50% off)
71 The Saboteur $4.99 (75% off)
79  Mirror's Edge $4.99 (75% off)
Pacific Pack $4.50 (90% off)
Gatling Gears $4.98 (50% off)
Warp $4.98 (50% off)
75% off Grand Theft Auto titles
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GameFly
67 Test Drive Unlimited 2 $9.99 (50% off)
78 Blur $4.99 (75% off)
86 Need for Speed: Hot Pursuit $4.99 (75% off)
78 Driver San Francisco $7.49 (75% off)
80 Need for Speed: Ultimate Digital Collection $11.99 (60% off)
86  Dirt 3 $19.99 (60% off)
Dirt Showdown $19.99 (60% off)
Pole Position 2012 $4.99 (75% off)
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Get Games
79 Metro 2033 $4.99 (75% off)
75  Warhammer 40K: Space Marine $7.49 (75% off)
75  Ghost Recon: Future Soldier $19.99 (50% off)
87  Deus Ex: Human Revolution $7.49 (75% off)
67  Aliens vs. Predator $4.94 (67% off)
64  Alpha Protocol $4.99 (75% off)
The Trouble With Robots $9.49 (50% off)
Company of Heroes Gold $7.49 (75% off)
Shoot Many Robots $4.99 (50% off)
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Green Man Gaming 
20% off downloads via coupon code "GMG20-FXYD1-7WHP1"
75% off select GTA titles

GOG
60% off Ubisoft titles
Pay what you want for the Divinity Anthology