I have been lately hearing to the Shanti Mantras and each time I hear to them, I feel tranquil and joyful. I suggest to buy a Shanti Mantras CD, one of it is 'The Chants of India by Pandit Ravi Shankar'. Play it while you are eating, just before you are about to sleep or even when you are cooking, doing your asanas or taking a shower. It is a very peaceful experience. I have got some information from wikipedia that I have shared below and it might be useful to you.
The Shanti Mantras or "Peace Mantras" are Hindu prayers for Peace (Shanti) from the Vedas. They are also recited at the beginning and end of religious rituals and discourses.
Shanti Mantras are found in Upanishads, where they are invoked in the beginning of some topics of Upanishads. They are supposed to calm the mind of reciter and environment around him/her. Reciting them is also believed to be removing any obstacles for the task being started.
Shanti Mantras always end with three utterances of word "Shanti" which means "Peace". The Reason for uttering three times is for calming and removing obstacles in three realms which are:
"Physical" or Adhi-Bhautika,
"Divine" or Adhi-Daivika
and "Internal" or Adhyaatmika
According to the scriptures of Hinduism sources of obstacles and troubles are in these three realms. Physical or Adhi-Bhautika realm can be source of troubles/obstacles coming from external world, such as from wild animals, people, natural calamities etc. Divine or Adhi-Daivika realm can be source of troubles/obstacles coming from extra-sensory world of spirits, ghosts, deities, demigods/angels etc. Internal or Adhyaatmika realm is source of troubles/obstacles arising out of ones own body and mind, such as pain, diseases, laziness, absent-mindedness etc.
These are called "Tapa-Traya" or three classes of troubles. When Shanti mantras are recited, obstacles from these realms are believed to be pacified.
Below is one of the Shanti Mantra that I have been hearing to lately. It is in Sanskrit and later translated in English.
ॐ सह नाववतु
सह नौ भुनक्तु
सह वीर्यं करवावहै
तेजस्विनावधीतमस्तु मा विद्विषावहै
ॐ शान्तिः शान्तिः शान्तिः
om saha nāvavatu
saha nau bhunaktu
saha vīrya karavāvahai
tejasvināvadhītamastu mā vidvishāvahai
om śāntihi śāntihi śāntihi
Om ! May He protect us both together; may He nourish us both together;
May we work conjointly with great energy,
May our study be vigorous and effective;
May we not mutually dispute (or may we not hate any).
Om ! Let there be Peace in me !
Let there be Peace in my environment !
Let there be Peace in the forces that act on me !
I will post some more Shanti Mantras..in the mean time you can google it and hear it. It is easily available on net! Till then feel Shanti and get nourished:-)