This displays a user's age on his/her page.
If someone wishes to have a similar funtion for their page, here is a quick "how-to" guide.
{{#ifexpr:{{CURRENTMONTH}} >= ¹ | {{#ifexpr:{{CURRENTDAY}} >= ² | {{#expr:{{CURRENTYEAR}} - ³}} }} }}{{#ifexpr:{{CURRENTMONTH}} >= ¹ | {{#ifexpr:{{CURRENTDAY}} < ² | {{#expr:{{#expr:{{CURRENTYEAR}} - ³}} - 1}} }} }}{{#ifexpr:{{CURRENTMONTH}} < ¹ | {{#expr:{{#expr:{{CURRENTYEAR}} - ³}} - 1}} }}
¹ - Month of Birth (As a number)
² - Day of Birth (As a number)
³ - Year of Birth