Want to meet other developers using Node.js, get a quick intro to 16 different topics, or build tools to solve real world water problems? Events on all of these topics, as well as many others, are taking place this week in Washington, DC. Below is a roundup of our picks for the week, and check out DC Tech Events for a full calendar.

Monday, October 17

7:00 pm

Big Data DC Meetup #5 : This month’s Big Data meetup will focus on Cassandra, with sessions on a new Cassandra query language and one looking at what’s new in Apache Cassandra 1.0.

Tuesday, October 18

9:00 am — 6:00 pm

TEDxPennQuarter : This local TED event focus on reinvention, with 20+ talks on reinventing things like newspapers, storytelling, medicine, hip hop, and beer. Tickets are still available for $99 a pop.

7:00 pm

BrainSquared : This month Netsquared is taking a new approach to its meetups and asking for full participation by everyone. Come ready to talk about a technology trend, challenge, or idea that’s been on your mind in casual conversations with other participants.

Wednesday, October 19

7:00–9:00 pm

Node.js Meetup : The third-ever Node.js meetup has two great talks on the lineup, with a presentation on testing Node.js web applications with the async testing framework expresso, and one on the multi-cloud datastore client Sunny.js. We’re hosting this in our garage and invite everyone with an interest in Node to attend.

Thursday, October 20

6:00–10:00 pm

Ignite DC #8 : In the always fun Ignite event, 16 artists, technologists, entrepreneurs, and philosophers will talk for five minutes on a topic they’re passionate about. If you want to quickly learn about some new topics and meet interesting people, this is a great venue for you.

Saturday and Sunday, October 22 and 23

All day

WaterHackathon : This weekend the World Bank is organizing a hackathon to bring together the brainpower of developers and water and sanitation folks to solve real water problems. Access to clean water and adequate sanitation is something that unfortunately way too many people do not have, and it’s great to see a local effort to solve specific water problems with technology. The DC hackathon is one of 10 happening simultaneously around the world.