Microsoft is expanding its Xbox Live Rewards program, with a "Play to Earn" initiative that tracks a virtual punchcard of purchasing progress. April's focus is strictly on Arcade games. Three separate rewards are being introduced, and gaining all three on your "MyPunchcard" will also grant you a spot as a "VIP," which earns extra rewards and drawings for more bonuses.
The rewards were announced on the Major Nelson blog. Playing 20 hours of any combination of Arcade games will net you a free item for your avatar. Purchasing any four Arcade games for $5 (400 MSP) or more grants you a month of Xbox Live Gold. Finally, spending $40 (3200 MSP) on games during the month will get you $10 (800 MSP).
The blog mentions that the punchcard system is all centered on Arcade games in April, but that implies that it could move into other ideas the next month. In other words, if you buy a ton of avatar hats, Microsoft will probably eventually have a month that rewards you for it.