No, Ethiopia have never entered the Eurovision Song Contest and they have never held the competition either.
Ethiopia is not in Europe, therefore they can not hold Eurovision.
Eurovision 2010 was held in Oslo, Norway.
The 1978 Eurovision Song Contest was held in Paris, France.
It was held in Moscow, Russia.
The Eurovision Song Contest 2009 was held in Moscow, Russia.
According to Wikipedia, the Eurovision finals are "traditionally held on a spring Saturday evening." It more often than not is held during the month of May. Read more about the Eurovision via the Related Link.
The 2012 Eurovision Song Contest was held in Baku, Azerbaijan.
No, Hungary are yet to win the Eurovision Song contest.
Eurovision 2013 will be held in Malmo, Sweden and presented by Petra Mede.
The Eurovision Song Contest is held in May at 21:00 CET.
Finland
Netherlands