Mahara is an open source ePortfolio system, developed in New Zealand and with a growing band of developers and users worldwide. The latest version 1.2 marks a significant landmark with the introduction of import/export functionality conforming to LEAP2A specification. If your school or organisation is looking for an environment for  personalisation, reflection and lifelong learning, then this is well worth a look. Read more in Tools for learning.

JISC and the British Library have worked together to make available nearly 28,000 hours of rare and previously unheard archival recordings as part of JISC's Digitisation Project. This is an incredibly rich resource for oral history and well worth exploring to source content in other subject areas such as music technology, history, art and literature.
Search the public collection or search across all 44,500 recordings if you are in a UK FE or HE organisation. There are some emerging case studies on how teachers and lecturers are using this resource.

Tired of the same old PowerPoints? Prezi offers a great alternative to the slide by slide approach. A Flash based tool, it allows non-linear presentations/visual maps which can be zoomed in on specific words, phrases, videos, images etc. The free version offers 100mb of storage and an offline player. Here's an example from their site.

Don't forget PowerPoint just yet though, if you want to explore similar functionality, download Microsoft's pptPlex plugin.

LibraryThing can be best described as a social networking site for book lovers. Combining a mix of social bookmarking, blogging and Amazon style functionality, LibraryThing offers a great way to share book lists and connect with readers with similar interests. It can be used to support teaching in a number of ways and has the usual range of widgets and embeddable tools you would expect from a social website.

myUdutu is a free content authoring tool, with which you can build your own interactive courses and integrate existing content such as PowerPoints. It enables scenario and branching activities, quizzes and supports video and audio files.
SCORM conformant Learning activities can be exported and uploaded to a LMS (or even put it on a memory stick or CD), or for a charge Udutu can host content for you.

Poisson Rouge is an interactive site for early childhood and young learners enabling them to develop their mouse skills through a range of activities, including English, French and Spanish alphabet games.

Whilst confusing for some adults, the site is deliberately designed for young learners to explore and discover. Don't worry, though, there is a user guide for any teachers who really want one!

xTimeline is a great tool with applications across many curriculum areas, particularly History and the Sciences, but in fact any subject where visuals and chronologies are relevant