Not every gathering you have should feel like a youth rally. But this one should. Have a night of worship where students can connect with God in a deep and meaningful way. Some teens are bad at worshiping God. The only way they'll get better is if worship is demonstrated for them. Provide them with a great atmosphere and give them an opportunity to passionately worship the Creator of the Universe. This isn't something that will attract the unchurched but it's definitely good to give your students a time of refreshment while they leave their burdens behind and focus on glorifying the Savior.