From English101.com.
I like Number 6 and 9.

1. Listen to audiobooks while walking.
2. Listen to your favorite podcast while walking.
3. Study free online language lessons on your phone.
4. Read books in the language you are learning on the train or bus.
5. Communicate online with other language learners.
6. Practice your writing in a document editor.
7. Use a flashcard application to improve your vocabulary.
8. Look up new vocabularies for things you see on the train or bus
9. Watch conversations and silently repeat what you heard.
10. In the target language, try talking to the person sitting next to you on the bus.
11. Try to listen to the train announcements.
12. Write down today’s transportation schedule in the target language.
13. Send a short message to my online tutor in the target language.
14. Repeat one interesting line in the target language silently or out loud.
15. Use a translation application to learn what the announcements mean.