Most of these articles can be read in 10-20 minutes. This makes them ideal for utilizing time during commuting. Use a smartphone application like Pocket and Instapaper, or send them to your Kindle.
In Hungarian:
A great proportion of the following books was published more than 15 years ago. Be sure to get the latest edition if you can.
Books by magician and mathematician Raymond Smullyan:
Light reads in mathematics: