Strategy fans will be pleased to hear the Deal of the Week this week, January 10-16, includes up to 50% off some of the top Tower Defense games available on XBLA:

Defense Grid – was 800 MSP, now 400 MSP
Orcs Must Die! – was 1200 MSP, now 600 MSP
Dungeon Defenders – was 1200 MSP, now 800 MSP
South Park: Let’s Go Tower Defense Play! – was 800 MSP, now 400 MSP

As always Deal of the Week is exclusive to Xbox Live Gold members.