Simon,
The function is =RAND()
This generates a (random) decimal every time the Worksheet is calculated.
If you're wanting to generate a random sampling of a specific list of numbers or names, I've put together a couple of different files, one of which will likely meet your needs.
If you'd like a copy of one of these files, email me and I'll send the file via return email.
Preferably, you should provide a little more specifics in your email as to what type of "random sampling" you require.
Regards, ...Dale Watson dwatson@bsi.gov.mb.ca