Science can be a difficult subject to teach under the constraints of time and curriculum set by school districts. By their nature children are curious and like to learn why the world is the way it is. A science fair is a way to give them the chance to tackle their own questions and develop hypotheses based on their own observations. It is also a way for students to learn the scientific method with a practical approach.
Whether or not your school is involved with the Let's Move program, a health and wellness fair is a way to make fifth-graders aware of their personal hygiene as well as the physical changes they're experiencing. You might make the changes that come with age a theme for the fair. While this fair will work successfully as a student-project oriented fair, what may make this an even more educational fair is to provide speakers from a variety of health and athletic professions. If the various booths also include an activity for the students to complete, such as a short quiz or game, it becomes a way to engage students in further examination of their own health.
History fairs are similar to science fairs in that they are a way for students to pursue their own questions. Set the fair around a specific theme. In an effort to strengthen the sense of community, teachers and students may want to try organizing a history fair focused on the history of the town they live in. Not only is it an educational opportunity, but it is also a way to spotlight the town, which may get more people to attend.
What they want to be they grow up is a question children begin answering before they understand the complexities behind having a job. A career fair gives you an opportunity to invite speakers to discuss their careers and how they got them. Part of making a career fair successful includes recruiting speakers who work in careers that students will be interested in. An interesting cross between a speaker-oriented and project-oriented fair may be to assign students to speaker, either individually or in groups, to spend a day with them and present what they learned with the speaker in a forum structure before their peers.