Daniel 5:1-6

Daniel 5:1
Belshazzar the king made a great feast to a thousand of his lords, and drank wine before the thousand.
At this point Nebuchadnezzar had been dead for some time.  Belshazzar was not the immediate successor to the throne of Babylon.  After the death of Nebuchadnezzar, the one who took his place was Evil-merodach who was Nebuchadnezzar’s son who reigned for eight years.  Jeremiah 52:31 (KJV)   And it came to pass in the seven and thirtieth year of the captivity of Jehoiachin king of Judah, in the twelfth month, in the five and twentieth day of the month, that Evil-merodach king of Babylon in the first year of his reign lifted up the head of Jehoiachin king of Judah, and brought him forth out of prison,  Belshazzar was the son of Evil-merodach and the grandson of Nebuchadnezzar.  He was not a major player in the historical records both biblical and secular.
Belshazzar was the typical politician who only concerned himself with good times and not reality.  At this point in Babylonian history, they were about ready to be conquered.  A few days before this event was thrown the Babylonians had suffered a major defeat by the hands of the Persians at Sippar which was approximately 50 miles (80km) north of the major province of Babylon.  The Persians were now at the gates of Babylon and judgment was about to fall on Babylon and Belshazzar who would die that very night.  This feast that Belshazzar threw was a large feast and it may not have been a thousand as a literal number but could have been a representative number of a very large gathering and it was a drunken feast where much wine was being drunk which was probably also representative of strong drink.
Daniel 5:2
Belshazzar, whiles he tasted the wine, commanded to bring the golden and silver vessels which his father Nebuchadnezzar had taken out of the temple which was in Jerusalem; that the king, and his princes, his wives, and his concubines, might drink therein.
Belshazzar was no doubt drinking himself into a daze had commanded that the gold and silver vessels which his father had taken from the temple in Jerusalem.   These were the holy vessels that the priests used to execute their temple duties.  Belshazzar had them brought out so they could be passed around and his guests could drink out of them.  He was no doubt showing that his kingdom conquered Judah and that Babylon was too big to conquer.  He was doing this in his drunken stupidity and he must have learned nothing from his grandfather about the God of Heaven.
Daniel 5:3
Then they brought the golden vessels that were taken out of the temple of the house of God which was at Jerusalem; and the king, and his princes, his wives, and his concubines, drank in them.
Then the king’s orders were obeyed and all the holy vessels from the temple in Jerusalem were brought out to the crowd and passed out among them so they could drink and defile them.  The fact that there were wives and concubines present meant that this was not a state or official feast but a drunken feast and orgy for pleasure and fun. 
Daniel 5:4
They drank wine, and praised the gods of gold, and of silver, of brass, of iron, of wood, and of stone.
They were drinking and partying and while they were doing that they were probably dedicating every drink or every bit of food to one of the false gods in their pantheon.  They were probably also singing the praises of their false gods.  During this time while they were drinking from the holy vessels, they might have been profaning the name of God but that was about to come to a sudden halt.
Daniel 5:5
In the same hour came forth fingers of a man's hand, and wrote over against the candlestick upon the plaister of the wall of the king's palace: and the king saw the part of the hand that wrote.
While they were starting to enjoy drinking out of the holy vessels a large hand appeared over one of the candlesticks, which was probably the biggest one so the writing would be more visible.  Then the king was able to actually see the hand that was doing the writing.  The words were written on the wall and possibly the words were engraved on the wall while the writing was going on.  Just like when God wrote the Ten Commandments for Moses, they were literally engraved on the tablets.  He made sure those words would not disappear.
Daniel 5:6
Then the king's countenance was changed, and his thoughts troubled him, so that the joints of his loins were loosed, and his knees smote one against another.
Then all of a sudden the king who had been having a grand old time drinking and partying, once he saw the writing on the wall (That is where we get the expression “The handwriting’s on the wall” when someone or some organization is facing a dilemma or defeat) his facial feature changed and no doubt it was to one of absolute fear.  He now began to be troubled as he tried to figure out what was going on or who was doing the writing or what it meant.  The sight of the writing hands had caused him so much fear that his joints literally were loosened by much fear and his knees starting knocking together.  This was no ordinary event and the king was troubled greatly and feared greatly.  This was probably prophesied back in Isaiah 45:1:  Isaiah 45:1 (KJV)   Thus saith the LORD to his anointed, to Cyrus, whose right hand I have holden, to subdue nations before him; and I will loose the loins of kings, to open before him the two leaved gates; and the gates shall not be shut;  God stated to Isaiah that He would loosen the loins of kings and Belshazzar was now being a fulfilment of that prophecy.