Memorial Day is America's unofficial kickoff to summer, but it's also a day to remember those who've given their lives in service to our country. (Not sure about the difference between Memorial Day and Veterans Day? Here's an easy way to remember.)

Memory itself is a funny thing. It's not always reliable, and it can color our lives in ways we don't even realize. However, remembering our collective past--and especially those who gave up their futures so that we could enjoy our present--is very important.

Here are 31 inspirational quotes about memory and sacrifice, all designed to get you in the right frame of mind to remember the spirit of this national holiday while you enjoy it.

1. "A hero is someone who has given his or her life to something bigger than oneself." --Joseph Campbell

2. "This nation will remain the land of the free only so long as it is the home of the brave." --Elmer Davis

3. "Never make your home in a place. Make a home for yourself inside your own head. You'll find what you need to furnish it--memory, friends you can trust, love of learning, and other such things. That way it will go with you wherever you journey." --Ted Williams

4. "Own only what you can always carry with you: know languages, know countries, know people. Let your memory be your travel bag." --Aleksandr Solzhenitsyn

5. "The legacy of heroes is the memory of a great name and the inheritance of a great example." --Benjamin Disraeli

6. "It doesn't take a hero to order men into battle. It takes a hero to be one of those men who goes into battle." --H. Norman Schwarzkopf

7. "Sweet is the memory of distant friends! Like the mellow rays of the departing sun, it falls tenderly, yet sadly, on the heart." --Washington Irving

8. "I've never tried to block out the memories of the past, even though some are painful. I don't understand people who hide from their past. Everything you live through helps to make you the person you are now." --Sophia Loren

9. Memories, even bittersweet ones, are better than nothing." --Jennifer L. Armentrout

10. "He was still too young to know that the heart's memory eliminates the bad and magnifies the good, and that thanks to this artifice we manage to endure the burden of the past." --Gabriel García Márquez

11. "When the soldiers came home from Vietnam, there were no parades, no celebrations. So they built the Vietnam Memorial for themselves." --William Westmoreland

12. "So long as the memory of certain beloved friends lives in my heart, I shall say that life is good." --Helen Keller

13. "Courage is almost a contradiction in terms. It means a strong desire to live taking the form of readiness to die." --G.K. Chesterton

14. "Famous men have the whole earth as their memorial." --Pericles

15. "And they who for their country die shall fill an honored grave, for glory lights the soldier's tomb, and beauty weeps the brave." --Joseph Rodman Drake

16. "Ceremonies are important. But our gratitude has to be more than visits to the troops, and once-a-year Memorial Day ceremonies. We honor the dead best by treating the living well." --Jennifer M. Granholm

17. "Who kept the faith and fought the fight; The glory theirs, the duty ours." --Wallace Bruce

18. "Life is all memory, except for the one present moment that goes by you so quickly you hardly catch it going." --Tennessee Williams

19. "Never throughout history has a man who lived a life of ease left a name worth remembering." --Theodore Roosevelt

20. "The key to immortality is first living a life worth remembering." --Bruce Lee

21. "History is a people's memory, and without a memory, man is demoted to the lower animals." --Malcolm X

22. "There are three side effects of acid: enhanced long-term memory, decreased short-term memory, and I forget the third." --Timothy Leary

23. "I am going to take something I learned over in Israel. Their Independence Day is preceded the 24 hours before with Memorial Day, so it gives them a chance to serve and reflect and then celebrate. I am going to try to start that tradition here in America. --Glenn Beck

24. "I don't want to repeat my innocence. I want the pleasure of losing it again." --F. Scott Fitzgerald, This Side of Paradise

25. "Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart." --Steve Jobs

26. "Sharing tales of those we've lost is how we keep from really losing them." --Mitch Albom, For One More Day

27. "I heard a definition once: Happiness is health and a short memory! I wish I'd invented it, because it is very true. --Audrey Hepburn

28. "These men were wrongfully rejected, the veterans. The fighting man should never have been blamed for Vietnam." --Neil Sheehan

29. "Without memory, there is no culture. Without memory, there would be no civilization, no society, no future." --Elie Wiesel

30. "A clear conscience is usually the sign of a bad memory." --Steven Wright

31. "Congress should stop treating veterans like they're asking for a hand out when it comes to the benefits they were promised, and they should realize that, were it not for these veterans, there would be nothing to hand out." --Nick Lampson