Hola, great site (but then you already knew that).
Anyways, here goes. I already removed two posts that were either covered/or in a wrong place.
The first, as already posted in Seasons is:
Glow - Use on an Umbrella (Sims 3: Seasons). Note that you need to lay the umbrella on the ground to actually upgrade it. It won't work if it is in your inventory. Also, it looks like it only makes the handle glow.
(Others have already covered the Laser Cannon and Space Travel Upgrades for the Flying Saucer)
There is another upgrade, though you may not wish to include it since it is for some official Store Content:
More Efficient(?) - Use on a windmill or solar panel. The windmill or solar panel would lower your bills by a set amount, and upgrading them makes it...er...more efficient. Please notice that the windmill or solar panel aren't in any normal expansion, but they are available as free store content from the Sims 3 main site.
I am unsure if More Efficient is the proper term as it appears there is a bug for the term. However, you can definitely upgrade those items.
One can currently find them in the Prius package on the main Sims 3 page. Just look for the little ad that says: The new Prius C. Go for a spin today! There is a package that includes the Wind Reaper windmill and the Heliosolaris III solar panel. )
A more direct link leads to the Prius, but the other stuff as well can be found here:
http://store.thesims3.com/prius
