There is nothing as fabulous as the smell of a church full of blooming lilies!! While I was growing up our church had them all over the altar and down the aisle at nearly every pew and they were glorious. My mom then brought ours home and planted them with her other bulbs. Sometimes churches now let people choose other types of flowers too. Of course, there's nothing inherently wrong with that. Easter lilies are a tradition and traditions change.
Whatever is the tradition at your church, sometimes people don't pick up their flowers after Easter Sunday worship. I've even known them to be (shhh) thrown away.
This year, if you have leftover lilies, why not donate them to a local retirement home, group home, or nursing home? I'm sure the residents would appreciate the cheerful flowers. You might even want to make arrangements for that ahead of time and let people know they have an option to donate their lily or other flower. Let the youth group deliver them and stay for a nice visit!