Today is the end of Hijriah Calendar Year, from 1429-H and approaching 1430-H. So, to all Muslims I would like to say HAPPY NEW HIJRIAH YEAR I MUHAARAM 1430 H.

Here is a little introduction about Hijriah Calendar quoted from Islamic Finder:
The Hijri date is the Islamic calendar. It started in the moon year in which prophet Muhammad immigrated from Makkah to Madinah.
The Islamic Calendar, which is based purely on lunar cycles, was first introduced in 638 C.E. by the close companion of the Prophet and the second Caliph, `Umar ibn Al-KHaTTab (592-644 C.E.). He did it in an attempt to rationalize the various, at times conflicting, dating systems used during his time. `Umar consulted with his advisors on the starting date of the new Muslim chronology. It was finally agreed that the most appropriate reference point for the Islamic calendar was the _Hijrah_. The actual starting date for the Calendar was chosen (on the basis of purely lunar years, counting backwards) to be the first day of the first month (1 MuHarram) of the year of the Hijrah. The Islamic (Hijri) calendar (with dates that fall within the Muslim Era) is usually abbreviated A.H. in Western languages from the latinized _Anno Hegirae_. MuHarram 1, 1 A.H. corresponds to July 16, 622 C.E.
The Hijrah, which chronicles the migration of the Prophet Muhammad (PBUH) from Makkah to Madinah in September 622 C.E., is the central historical event of early Islam. It led to the foundation of the first Muslim city-state, a turning point in Islamic and world history.
To Muslims, the Hijri calendar is not just a sentimental system of time reckoning and dating important religious events (e.g., Siyaam (fasting) and Hajj (pilgrimage to Makkah)). It has a much deeper religious and historical significance.
The Islamic (Hijri) year consists of twelve (purely lunar) months. They are:
  1. Muharram
  2. Safar
  3. Raby' al-awal
  4. Raby' al-tsaaniy
  5. Jumaada al-awal
  6. Jumaada al-tsaaniy
  7. Rajab
  8. Sya'baan
  9. Ramadhaan
  10. Syawwal
  11. Dzul Qaidah
  12. Dzul Hijjah
The most important dates in the Islamic year are:
1 Muharram (Islamic New Year)
27 Rajab (Ira' and Mi'raj)
1 Ramadhaan (First day of fasting)
17 Ramadhaan (Nuzul AL Quran)
Last days of Ramadhaan which include Laylatul Qodar
1 Syawwal (Eid al-Fitri)
8 - 10 Dzul Hijjah (the Hajj to Makkah)
10 Dzul Hijjah (Eid al Adha)

Photo source: Flickr.