One lambda application I really want is a pingdom-style service. Use lambda to ping a web site and send an email if it's offline. Any takers to build this :-)?
Actually, Amazon already did -- one of the sample Lambda functions you can use is just that. It runs on a scheduled timer, and if I remember correctly, will alert using AWS Simple Notification Service, which can be configured to send alerts to your devices or emails.
I'm building some nice example projects for claudiajs now, this sounds like a fun thing to try. check out https://GitHub.com/claudiajs in a few days, it will probably be there