If you want to know what mobile phones would've looked like 100 years ago (had they been invented), the Old Style Theme might give you some idea.
This eye-catching theme for S60 devices transforms your device to make it look like it was designed in the 19th Century. It adds a parchment-style background wallpaper to your home screen and in the background of the system menus. Personally, I thought the crinkled effect could've been done a bit more authentically though.
The new icons added by the Old Style Theme are excellent. The dark brown and beige color scheme works very well and the icon images themselves are clear and precise. I'm also a fan of the new analog clock style on the home screen.
For an old-fashioned twist on new technology install Old Style Theme on your phone.