A recent study by Google's AdMob found that gaming is the number one activity on tablets, followed by searching for information, and e-mailing. More info at CrunchGear.
In addition to the results above, the survey found that 82% of tablet owners are using their tablets at home, 62% at night — a perfect time for recreation. So you’d expect tablet usage on the weekend to also be high, but 69% of respondents said they use their tablets more during the weekday. How much more is unknown.
Based off this data, a stereotypical tablet user spends most of their time gaming, searching and emailing after the typical workday, leaving their tablets idle on the weekends.