When working on 20×4 (or bigger) lcds font dimension can become an interesting issue: [liudr] shared & updated its Phi_Big_Font library

The Phi_big_font library utilizes 3 X 5 dot matrix technique I developed to display characters 6 times the size of ordinary characters seen on HD44780-compatible character LCDs. You will need two rows and 4 columns to display one character (with one column blank to separate characters). A 16*2 display can display 4 such characters, making a perfect clock display like HH:MM, or month or day display in three characters. A 20*4 display can display 5 characters by two rows, totally 10. You can display the characters anywhere you want. Make an animation if you want.

via [Arduino Forum] source [liudr blog]