1. Go to a book reading and force yourself to ask a question of the reader.
2. The next time you hear an opinion on the radio that makes you angry, go to the library or the Internet and read as much as you can about that opposing viewpoint. (Or write a "counterpoint" to the opinion, without resorting to angry language.)
3. Join a book group. Better yet, start one! Instead of reading current best sellers, invite the participants to read classics from ancient Greece, or from nineteenth century England, or from the canon of great American literature.
4. Audit a class at a local university.
5. Memorize a poem. (Tip: Poems that rhyme are inherently easier to commit to memory.) The discipline of memorization gives you a deep appreciation for words and their rhythms, and allows you to summon up a favorite passage any time, in any place. Choose a poet you've always admired, or select a topic such as, well, gratitude! Two to start: Edna St. Vincent Millay's "God's World," written when the poet was just 20 years old; and e.e. cummings's "i thank you god."
6. Write a letter of thanks to someone, living or dead, who has fed your mind in an important way.