Enter by adding or improving a game page using the 'Edit' link on the game page. You can also make a post or comment in this forum and enter to win a $20 gaming playmat EVERY DAY at 4pm PST. Each improvement, post or comment is another entry.
Full rules here.
I'm hoping to encourage improvement to the database while also keeping the community active with this giveaway. Also, the contest start period is the moment yesterday's ended so that any potential posts weren't made in vain!