Mice, even wireless ones, usually follow the same basic shape, but there are some that don't do even that, like the Galex 24G.
Created by Spire, it is a light, ergonomic mouse that can do a lot of things most mice can't, all for the price of $24.95 / €19.95.
First off, it can fold in on itself, for easy transportation.
Secondly, it has intelligent zoom-in and zoom-out Internet functions, when it usually takes a CTRL+scroll up/down to do that.
The mouse can also work on any surface, except glass. No longer will a smooth wooden, slightly shiny surface give problems.
All in all, the feature set isn't bad for a mouse compatible with Windows MS 98 / ME / NT / 2000 / XP / Vista /7 / 8 operating systems.
All it needs is a USB 2.0 or 3.0 port, to plug the receiver in, and it's ready to go.