Pentecost.

Pentecost is celebrated 50 days after Easter.  It commemorates the 
descent of the Holy Spirit upon the Apostles and other followers of
 Jesus as described in the Book of Acts.  On the day of Pentecost, 
the followers of Jesus were all gathered together in one place and
 God sent the Holy Spirit to give them the power to teach others 
about Jesus. They heard the sound of a mighty rushing wind coming 
from heaven. They couldn't see the Holy Spirit, but they could hear
 the sound of the wind.  They saw what seemed to be flaming tongues
 of fire that came and rested on their heads. They knew the Holy 
Spirit was there because they could feel his power. When they were 
filled with the Holy Spirit, he gave them the ability to speak in 
languages that they didn't even know, so that they could tell 
everyone about Jesus. They couldn't see the Holy Spirit, but they
 could feel his power in their life.  The Holy Spirit is still with
 us today. We can't see him, but we can hear him as he speaks to 
our hearts, we can see his moving in our life, and we can feel the
 power of his presence as he guides us through each day.