TOPIC:

Observation:
Cleverly, if the value of a custom field is a URL (http://~some site~) it will be presented as a clickable link on the front end.

However, https://~some site~ will not.

Given that sites often force ssl I made the following change in <install>/components\com_jem\views\venue\tmpl\default.php:
From:
if(substr($currentRow, 0, 7) == "http://") {
To:
if((substr($currentRow, 0, 7) == "http://") || (substr($currentRow, 0, 8) == "https://")){

Additionally, rather than presenting the written URL as a link I made it a graphic...
From:
$currentRow = '<a href="'.$this->escape($currentRow).'" target="_blank">'.$this->escape($currentRow).'</a>';
To:
$currentRow = '<a href="'.$this->escape($currentRow).'" target="_blank"><img src="SOME IMAGE PATH" border="0" alt="SOME ALT"></a>';

Just to note:
With JEM 2.1.4 the https thing will be fixed on event and venue custom fields as well as on venue url field.