The Electronic Frontier Foundation (EFF) is the subject of a profile in Wired magazine. For those of you unfamiliar with the organization, it's a sort of ACLU with a strong technology bent and they've been at the forefront of issues such as the SONY/BMG case which dealt with copy protected CDs and where their intervention helped win a settlement that assures that the users who were duped into purchasing the copy protected music get unfettered access to their tunes. The article covers much more, though, and is worth a read, especially if you don't know the organization.
For those interested in the history of the organization, there's more on the EFF web site, including a thorough archive of every case they've been involved in since the original Steve Jackson Games case that precipitated the EFF in the first place.
In addition to the suing people (including recent suits of AT&T over the disclosure of phone records, the EFF also regularly provides its views on legal issues on the web and it also funds Tor, a system of proxies that anonymizes access to the internet, thus allowing people to search without effectively being tracked.
You can, of course, contribute to the EFF if you feel that it is in your best interests and worthy of your support.