A couple of Lambda functions that combine to support the mini-website at IsItOnAWS.com
The Lambda function in newranges.js is subscribed to the SNS topic announcing changes to the IP-Ranges JSON resource. It retrieves that resource and generates another function based on the code in isitonaws.js, including a form of the IP-Ranges compiled to make it easily searchable.
To show a bunch of different AWS services working together to produce a hands-off, simple, serverless mini-app.