Learning Names
Icebreakers are games that introduce kids to others they don't know well, which may be useful for new youth groups or at camps. An easy icebreaker is to sit in a circle and have the first person tell their name and something interesting about themselves, and then next person recites what the person before them said and adds their own name and interesting fact. As the game progresses around the circle, the kids have to say the names and facts of every person before them. The game gets much harder for those at the end of the circle, so consider having kids line up by age before forming the circle and making the older ones go last.
Tag
Tag may seem too simple or overdone to play with a youth group, but sometimes simple is best. Most kids will be used to playing tag in an open field or gymnasium and not inside a large building with hallways and multiple levels. Playing a church-wide game of tag can be fun way to let kids to expend some energy. You can create rules as to where in the church people can go based on the size of your group: smaller groups should play in smaller areas.
Sardines
Sardines is another game that utilizes the church building itself to create a game. Sardines is essentially hide and seek where one person is "it" and tries to find everyone else, except that that each person that is found joins the searcher to find the other people. Another difference is that the people hiding can move around to avoid being found. This game works quite well since the original searcher is likely to stumble on a few people quickly and once there are many searchers is becomes easier to find people that are well hidden or that move around constantly.
Trust Games
Building trust between youth group members can be a good way to promote bonding. A common trust game is the trust fall. In its most basic form the trust fall involves one person falling backward with their eyes closed into the arms of another person that stops the fall. In a more advanced version of the trust fall, you can have a person stand up on a chair or table, and have eight or more people link arms behind them in order to catch them. Blindfold games are another way to build trust. Having half the kids put on blindfolds and the other half lead them around the church only using verbal directions can be a fun game.