This file modifies the text the game displays while loading. Instead of the default text which is funny for a day or two but gets old after time, you get the following:

Waking up the Reaper
Loading Kathy's Basement
InSimenating the InSimenator
Error-proofing the Forum Database
Lowering Ethical Standards
Corrupting Your Downloads
You Didn't Need that File Did You?
Ruining Your Sims Lives
Making Doors Stick Open
Reformatting Your Hard Drive

If you should tire of these, by all means open the file in SimPe, click on the EP/SP Startup Strings file for the newest expansion/pack that you have and change the text to whatever you like.

Only download the file that corresponds to the latest expansion you have. There is no file for the holiday pack, sorry but that is one that I dont have. The expansions in order:
TS2 - base game
UNI  University (EP1)
NL  Nightlife (EP2)
OFB  Open for Business (EP3)
FFS  Family Fun Stuff (SP1)
GLS  Glamour Life Stuff (SP2)
Seasons (EP5)

This file goes in your downloads folder. Should you need to remove it or wish to alter it, its name is UIText.package. If you upgrade your game and come back for a later file, simply extract the new file to your downloads folder and tell it to overwrite.

Enjoy! :)