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The two games are Poppit and Entanglement, and if you're running the Dev channel, by now you should have noticed them in your New Tab page. They just showed up there, without any prior notice or you having to do anything. What's next Google, a McAfee trial version with Chrome 11? Although unlike pesky anti-virus trials, the two games can easily be uninstalled if you so wish.
But since they're there, perhaps you should give them a try. They are supposedly HTML5-heavy, so besides being worthy time-wasters, they might also serve as useful showcases of what can be accomplished with the next generation of Web technologies. Or not. Your call.