Variables

 
 
 
?
*
+
{n}
{n},
{m,n}
Digits: \d (0-9)
Word character: \w [a-z 0-9)
Space: \s
 
Zero or one of the preceding element. 
Zero or more of the preceding element. 
One or more of the preceding element. 
Exactly n of the preceding element. 
n or more of the preceding element. 
Between m and n of the preceding element

Example - one or more spaces:  \s*
Example - three to five digits:  \d{3,5}
Example - exactly one word character: \w
 
Time & Dates
Tuesday, October 15, 2008

^(Monday|Tuesday|Wednesday|Thursday|Friday|Saturday|Sunday),\s*(January|February|March|April|May|June|July|August|September|October|November|December)\s*\d{1,2},\s*\d{4}\s*$

 
31 January 2003 | 29 March 2004 | 29 Feb 2008 

^((31(?!\ (Feb(ruary)?|Apr(il)?|June?|(Sep(?=\b|t)t?|Nov)(ember)?)))|((30|29)(?!\ Feb(ruary)?))|(29(?=\ Feb(ruary)?\ (((1[6-9]|[2-9]\d)(0[48]|[2468][048]|[13579][26])|((16|[2468][048]|[3579][26])00)))))|(0?[1-9])|1\d|2[0-8])\ (Jan(uary)?|Feb(ruary)?|Ma(r(ch)?|y)|Apr(il)?|Ju((ly?)|(ne?))|Aug(ust)?|Oct(ober)?|(Sep(?=\b|t)t?|Nov|Dec)(ember)?)\ ((1[6-9]|[2-9]\d)\d{2})$