"Logical and fun"
OSMO is an excellent educational and entertaing tool that binds together iPad apps and real world accessories. Check out this post to know more about it.
In Tangram for OSMO, kids must try to build elements using the physical shapes. The app shows the object they must reproduce. Then, when they put together those pieces in the expected order, the match is done and the iPad app displays it and pushes a sound notification so they know they are on the right track. Of course, the more objects they build properly, the higher the score.
Tangram is perfect for 4-6 years old kids. One of the OSMO games that best achieve the balance between education and entertainment.