We tend to have several long (6-7 week) sermon series each year at Northview. To help tie things together, we usually have some sort of metaphor, or image, or stage design piece. Sometimes, a simple color can function as the unifying factor. For example, in 2010, we borrowed a series from Crossroads in Cincinnati, and used the color orange as the thing that held everything together. We painted our drum and keyboard risers orange, our info center in the lobby turned orange, etc… Not everything (that would be overkill), but enough to tie things together.
Here’s a color palate that you might use if you have a sermon series based on the Muppets:
creativeworshipideas 