MapReduce in MongoDB
One of the first things I took on when joining OpenTable was building a new endpoint in our reviews API to aggregate and summarise restaurant review data. Thankfully, at the time, all the data I needed was cached in memory so building the response object was a simple set of linq queries over the cached reviews.
nLocalGeoCoder
With OpenTable having engineering teams spread across multiple offices it's important for us to maintain open email dialogue about new products us or our teams have created, new tools we've discovered or problem solving approaches that have helped us achieve our goals. Recently in one of these emails Aish introduced the team to a new open source ruby implementation of reverse geocode lookup for latitude and longitude he'd written called local-geocoder. With an interest in understanding how this worked, to learn a bit of ruby, to make this project accessible to .net developers and just to see how long it would take I decided to port it to C# and .net.