I had an arduino board and the books "don't make me think" http://www.amazon.com/Think-Common-Sense-Approach-Usability/... and "programming clojure" http://pragprog.com/titles/shcloj/programming-clojure
So far the best project I want to aim for is a UAV (http://www.diydrones.com) - either that or as a controller unit for a coil gun.
Any other suggestions for us?? :D