I know that around this time of year, a lot of people are in a giving mood. And it's not just limited to exchanging gifts, but also donating to charity. In addition to the humanitarian causes that many people support during the holiday season, consider helping out these somewhat geekier groups too.
The Internet Archive
The definitive historical record of the web — and other media too! The new fact-checking TV News Search system alone is eminently worthy of support.
Wikipedia
There's no way you haven't seen the banner at the top of their pages countless times already, so I won't reiterate here all the good work they do. Just consider how many times you must have used their site this month alone.
The Electronic Frontier Foundation
Since the early days of the Internet, the EFF has fought to keep it free and open. The 'net as a whole would be a very different place today without them — but that doesn't mean the work is over.
The American Civil Liberties Union
Even for non-Americans like me, the dominance of US-based media and Internet companies means that the ACLU's work has far-reaching consequences well beyond their national borders. For those within the US, their importance is even greater.
Bletchley Park
A lovely historical site and museum of not just a fascinating piece of military history, but computing and cryptographic history too. Having been there recently myself, I can attest to the fact that they have an excellent museum and a great set of staff and volunteers, but the ageing infrastructure is indeed sorely in need of financial support.
The FreeBSD Foundation
Technical excellence and truly free code are what characterize FreeBSD. The liberal licensing has always meant that many others benefit from their work, even if they don't run FreeBSD themselves.
Mozilla
Constantly pushing the Web forward, Mozilla can take more than a little credit for the rich online systems we enjoy today. I know for certain that Firefox is by far the most used application on my computer — and it's all free.
Any others that should be on this list? I'll happily update it with suggestions! What's your favourite technical cause in need of help this year?