The big event in Lopez Village is the 4th of July, with a parade, fun run, barbecue, and fireworks. In addition to being loads of fun, the event funds the public shower facilities in the heart of Lopez Village.
Also of note is the Tour de Lopez (360/468-4664, www.lopezisland.com/tourdelopez.htm [1]), a noncompetitive bike tour of the island held each April. Riders choose from routes of 10–26 miles and are treated to lunch in the village once they've pushed their last pedal.
Links:
[1] http://www.lopezisland.com/tourdelopez.htm