Cool Math website

Origo Education [source]
" ORIGO was established in 1997 when co-founders James Burnettand Dr Calvin Irons identified the need to meet a growing demand for professional development in mathematics. With the vision of making a positive contribution to children's education, James and Cal began writing and producing mathematics resources from a makeshift office in James' home. Today, ORIGO provides a complete education solution to its customers by combining an innovative range of mathematics products with quality professional learning services. "
Some details here: http://www.origoeducation.com/developing-essential-strategies-for-computation/

So perhaps an abacus and marbles could be useful as tangibles, and/or in computer applications...

And this article is also very interesting: Math made easy - Thinking Strategies in Primary Mathematics
http://www.origoeducation.com/assets/pdf/MathsMadeEasyCM.pdf
There are quite a few tangible tricks in this article that could be cool to play with, perhaps using LEGO (?)

Papier-mâché

1- a recipe to make the "glue" with just flour and water [video]
2- an example: how to make a mask [video]
3- how to make a cat [video]

Create sentences and stories... by rolling dice!

Soft Touch™ Dice: Sentence Building Complete Set
'' Practice building sentences by rolling word dice, putting them in order, and recording the sentences that are built. Set 1 focuses on simple sentences while Set 2 adds additional parts of speech to build more complex sentences. The color-coded dice help players recognize parts of speech and word order, which support English Language Learners. '' [source]

Incredible machines built with LEGO!

'' Machines have long been used to ease repetitive labor. Some machines eased the labor of calculation; watches, orrerys, calculators, difference engines, etc. Gears were the workhorse of this age reaching the zenith during the late 19th century only to decline as they were replaced with transisters for most computation.
...

Babbage Difference Engine made with LEGO

This is the 3rd generation of Babbage Difference Engine made with LEGO. It is modeled after Babbages Difference Engine #1. The 3rd generation operates five times faster than the 2nd generation.

This machine can evaluate polynomials of the form Ax^2 + Bx + C for x=0, 1, 2, …n with 3 digit results.

...

Antikythera Mechanism (Eclipse Predictor) made with LEGO

This machine, modeled after the ancient Greek original, can calulate the date and time of solar and lunar eclipses over a hundred year period.

It is an analog computer with over 100 gears and 7 differential gearboxes. It is accurate to a day or two over it's range.

'' [source]

Also this project is very interesting, showing how make a working 7-segment display with lego technic [video]

DIY paper Mecha!

- Goldrake (aka Grendizer, aka Goldorak) 

- Another version of Goldrake, this time with spacer [source]:

- mini mazinger [source]

- Generic (but really cool) paper-robot [source]:

- and for these kinds of paper toys, this site looks really nice: http://paperkraft.blogspot.com/

Interesting modular toys

Blockheads

[source]

Toy Studio (MIT)

 [source]

In particular this last image suggests an actual setup with small interactive tablet-like devices, that could be combined to form a city or a circuit...
It could be fun to try something like this, and the result would be a mix of my c-cards and Emanuela's microculture.

Origami camera!

[source]