Best Answer - Chosen by Voters
I googled New Year's Eve 2009 Mayo, and then tried for Galway
There were many gala banquets and balls in both places, and for Achill I found the following
At midnight on New Year's Eve the many local pipe bands welcome the New Year with a rousing and unforgettable chorus in each village. Follow the marching bands through the many villages to there meeting point at Pollagh Church and carry on the night as you may wish with some dancing or return to the pub and join in the craic till the wee hours.
If you are daring, brave, adventurous .... New Year's Day there is an annual swim in the Atlantic waters of Achill at the Golden Strand, Dugort. Not that daring.... you can just go to watch the fun event