[MickDoneDee]

Thanks for that useful mod, Dream. I'd also like to order "Currently Active Users" on FORUMHOME by lastactivity. How do I do that?

Update:

The order of loggedinusers is selected in admincp:
vBulletin Options > Forums Home Page Options > Display Logged in Users?

Displays those users that have been active in the last XXX seconds on the home page, where XXX is the value specified by your Cookie Time-Out option (Default is last 15 minutes). Not recommended for sites with hundreds of simultaneous users. The Alphabetical option requires more resources than the random option.

Only two options are available: Alphabetical or random.

The index.php file has a section:
// ### LOGGED IN USERS ###################################

a few lines below that is:
WHERE session.lastactivity > $datecut
" . iif($vbulletin->options['displayloggedin'] == 1 OR $vbulletin->options['displayloggedin'] == 3, "ORDER BY username ASC") . "

username can be replaced with lastactivity which overrides the vbulletin options setting.