I recommend going to
http://www.neoitems.net and looking through the items and see what appeals to you. Being creative is only a short brain fart away. Most unique gallery idea I've shared is a Shadow Gallery (A Gallery consisting of items who cast a shadow in thier images) A Food Face Gallery (a collection of food that can smile back) and a Leaf Recycling Gallery (which contains all items that use recycled leaves like books, food, and furniture). Being specific keeps the gallery from being gia-normous.
For you, I recommend things that steam!