A very common problem in Ubuntu is "how the heck do I change the first day of week to Monday?". One can google and find a lot of solutions with locales "hacking". Is there a simpler way to do that?

Yes, there is! At least in Ubuntu Lucid Lynx with GNOME v 2.30

Step 1
Open Language Support dialog


Step 2
Change your format types to e.g. UK format


Step 3
Restart your computer (or just restart GNOME).

There it is!