Wall mirrors are a great way to add some punch to a room, while also opening up the space and making it seem bigger. Melissa at 320 Sycamore DIY'ed this great 'wall-o-mirrors' for her daughter's bedroom. Total cost $19.98:
Yes, you might need to re-learn a little geometry for this one (where's that protractor, anyway?).
Wall O' Mirrors [320 Sycamore]
If you need a little more inspiration, check out Capree's post about making your own sunburst mirror for under $25: