This is probably one of the oldest and most well known icebreakers. It's also known as "People Bingo" and "Get To Know You Bingo". It works for groups of all ages, and can be a really interesting game if played properly.
You'll need to create a name bingo sheet, so basically a 4 x 4 or 5 x 5 grid of personal statements. IE. "has long hair" or "has more than 5 siblings" or "has travelled overseas" etc
Hand these people bingo sheets out to each person and give them a pen, and then send them off to mingle and find people that fit in the gaps. Each player can only use another person once on their sheet.
So the game can either finish when someone collects a name for the entire grid.
Alternatively, the game can continue and bingo can be played after everyone has completed their grids. So a leader would start reading out the names of the youth group kids and then they would need to cross off a name when it has been called - if they get 4 in a row - they win!