You can find printable cryptograms at many online puzzle sites. Printable-Puzzles.com and Puzzles-to-Print.com offer a few sample printable cryptograms for you to download. When you need more puzzles, you can go to Cryptoquote-Cryptogram-Puzzles.com to download even more cryptograms.
Cryptograms are puzzles where a length of text has its letters changed so that you cannot read the text directly. The letters are changed in a systematic fashion which allows the puzzle to be solved. The length of text can be as short as a sentence or as long as a paragraph. Humorous sentences, famous quotes or passages from famous books are usually used as the base text for the cryptogram.