In fact you can emphasise that in some cases, the more way out the idea the better. The ideas generated during a brainstorming session are ideal for use when planning a valuable and interesting Unit of Work. Group work is great fun on most occasions in the classroom but can be really valuable when you are having some difficulties getting the message across because learning from peers is a most effective learning strategy. It is important that groups be fluid ability, friendship, teacher directed or random using simple jigsaw puzzles etc which need to be solved to find group members. Try cutting some magazine pictures into as many pieces as you want group members.
Overhead projectors Have clear space so that children can read what is presented.
OHPs are great for imaginative art activities, enlarging drawings, group or whole class instruction, proofreading and conferencing techniques etc. Try to have spare globes on hand as it's really frustrating if the globe goes in the middle of a lesson. Big books require a suitably sturdy stand which won't collapse as you turn the first page, and bookshelves should contain an interesting display of books from library or ed. centres. Cooperative Learning Centres provide an interesting array of hands on activities suitable for all ability levels. Use what is essential for an interesting presentation don't turn your creative introduction into a vaudeville act without a purpose.