This document is an invitation to a MongoDB meetup on April 4th 2014 presented by Ryuji Tamagawa. The agenda includes: - An overview of what MongoDB is and how it stores JSON documents. - Trying MongoDB using Vagrant to avoid compatibility issues across attendees' machines. - How Vagrant creates clean, isolated virtual environments for hands-on sessions. Key points about MongoDB include its hybrid nature between SQL and NoSQL, support for secondary indexes on JSON fields, rich drivers in many languages, and easy replication and sharding capabilities. The talk aims to demonstrate a replica set using a sample project hosted on Bitbucket.