Syntax

edit
{{User:Cuckooman4/UBX/Age
  |age
}}

Source

edit
<div style="float: left; border:1px solid #053A83; margin: 1px;">
{| cellspacing="0" style="width: 238px; background: #99CCFF;"
| style="width: 45px; height: 45px; background: #053A83; text-align: center; font-size:15pt; color: #fff;" | '''{{{1|0}}}'''
| style="font-size: 8pt; padding: 4pt; line-height: 1.25em; color: #000;" | This [[Wikipedia:Wikipedians|Wikipedian]] is {{{1|0}}} year{{#ifeq:{{{1|}}}|1||s}} old.
|}</div>

Note

edit

I didn't completely make this userbox, I simply edited Template:User current age.